Just to get some discussion going, here's how I see 8th affecting each one of our units, given the current rumors:
Skink skirmishers
Supposedly skirmishing formation is now just a rank and file formation. I've heard 360 LOS is both out and in. I've also heard they'll be able to break ranks with enough models to form a second "rank", and that they won't. Everyone is saying they get to march and shoot, though, and with M6 having to wheel or whatever won't kill them. Relaxed LOS restrictions mean hitting more stuff but cover will kill any chance of poison, and screening may not be as valuable. Basically, I don't think these guys are going anywhere; they'll almost for sure play different, but are still cheap and have strong shooting options (given the weaknesses of the rest of the army).
The forced formation will be a bit of a minus but increasing skinks blowpipe poison range from 18 to 24" is truly horrendous for our enemies! major boost imo.
Skink cohorts
Definitely one of our beneficiaries of the new rules. Parry ward might keep them alive. Two ranks will help vanilla blocks but will put skink-krox blocks a bit behind (as the second rank will be about three skinks). 10 wide might actually work, esp. with krox, but the same problem remains of not getting much benefit from it. I think pure skink blocks are going to get scarier, and Skink-Krox blocks are going to lose some of their edge, unless there's some way to work getting a second rank of krox or the skinks behind the krox into combat.
I don't think skink krox are really losing much on the offensive which you seem to consider a negative., your complaining about losing 2 S2 attacks? Their main problem is their T2, now that everyone is attacking more, generally with s3 or s4 this means skinks will be taking a lot more casualties, at 5pts a pop you can take units large enough to get stubborn and with a slanns ld9 and cold blooded you won't be breaking, that said the unit does little else above adding the 3 cr from ranks and holding the enemy in place, min price for this ability is 200+ points, temple guard do it cheaper. I don't see normal skink units working very well, probably not with the skink krox either.
Saurus warriors
In a funny spot. Low I, but never got the charge anyway. Spears have been scary, but now only matter with a third rank, killing the popular 6x2 spear saurus. Instead we get 18 S4 and a 6+ ward from 6x2 HW, or the same thing with 24 S4 option and wound insurance from a 6x3 spear block. Also, character system means we might be able to sneak several mundane-geared Scar-Vets into saurus blocks. Spear saurus had a brief rise to fame but overall I think they're going to be stronger when invested in heavily and maybe a little weaker when 6x2s or 5x2s are just used to fill core (a result I'm happy with).
With the stepping up rule all models in the first two ranks get to attack, saurus have rather high toughness and armour, the low init won't matter much as long as you have a few spare models to actually step up. I might change my 3*6 with spears to 3*6 with HW/shield myself.
Jungle swarms
Not even really sure what the rules are going to do to skirmishing monster-base swarms, but removal of outnumbering might help with crumbling. Dunno, seldom field them.
Chameleon skinks
I've always liked these guys, even though most don't. I think they're about to get a
lot better. The new shooting rules will let them pull some funny business with BS4 blowpipes, and 60 points for 5 was only ever bad because it ate a valuable slot. Now, with it coming out of a very generous allowance (50% of game size) it's more or less cost-free to field them. It will be a rare game that I don't take 3 units (or whatever the spam limit is) of 5 to just kind of handle problems. Skirmishing changes as mentioned for normal skinks will not apply as heavily due to small size and scouting helping with setup.
They do lose their ability to run around between the enemies army, the forced formation is unlikely to allow it even 1/2" between each model, that still makes for something like a 5" wide formation, still their shooting is nice and with the cover granted by being in a forrest or other terrain they become virtually impossible to shoot while in cover. Release of slots is nice but I don't see a huge benefit in these guys over normal skinks apart from the scout rule.
Kroxigor
This is another 7th about-face. After our 7th book these guys started looking weak as a special choice but very strong in Skink blocks; I think it's about to turn around. Rumors and demo games say 3-wide ranks for monstrous with up to 3 attacks from the back rank; 3x2 Krox getting 18 S6s is pretty good, with an additional 6 S4 at end of combat, and +1 combat res to boot. A 6x3 will also be one of our rare options for offensive rank-breaking. It will be an expensive unit, but an effective one. In smaller counts their use will be hampered by the new inability to break ranks or strike first on the charge, meaning they're going to lose to static CR a lot more often. Larger units better, smaller units worse. (I guess that's the pattern

)
6*3!? that's madness, 990pt unit, I don't think so. I think the 3*2 you mentioned will be killer if it works out, 18 S6 attacks are indeed fairly scary, and M6 + fear on top is just gravy, though they cannot take musicians which might make their movement a little harder, still with M6 I think they can manage. My 10 krox might actually see the table again.
Stegadon
Ugh, I don't want to talk about it. Can't break ranks, impact hits don't prevent return attacks (and may no longer exist), no flanking bonus, and no autobreak. The days of running these guys straight through an army flankwise are gone. Rumored to get D6 extra attacks at end of combat, but also rumored this might be
instead of impact hits, so who knows. Combat res is going to be a race against ranks and free kills on the skinks up top. Also, warmachines are supposed to hit all parts of a model with a touch, now, so one cannonball or stone thrower template (that range does not have to be guessed for) will obliterate all of the skink crew. Much more of a tarpit unit now. Bolt thrower on top is a bit better but seldom hits. I'd go with the Krox, personally.
Temple guard
Now we're talking. Two rank halberds (although the Slann will displace two) is going to be
disgusting, and HW+S will be stronger than present. Greater difficulty breaking ranks means more units bounce off, and 2d6 charge means you can try to get them in combat sooner. Stronger than ever, and worth fielding on their own without the Slann IMO.
With no autobreak from fear, the slanns immune to psych is no longer needed so yea you could start seeing them without someone to bodyguard. How do you see HW/S being better, its clearly worse, against S3 you now get a 3+ and 6++ instead of a 2+, meaning you take almost double damage, agast S4+ well the difference is less but its still worse
Cold One Riders
Meh, sounded cooler as Cold One Cavalry, IMO. Anyway, these guys have always been kind of weak compared to Stegadons and Kroxigor. With new rules you'll need a second rank to break ranks, you won't get to attack first on the charge, and your second rank gets one attack. You're looking at a similar cost to a 3x2 krox unit to be able to break ranks and put an equivalent number of attacks, and you're more vulnerable to chance wounds. Upside: 3d6 on the charge, meaning the relatively low M7 for cavalry doesn't matter as much. I really don't think these guys are going to beat out our other options, but could use a little testing, I guess.
Terradon riders
This is another unit that hangs in the balance. Skirmisher rules will affect flyers, and our Terradons might be affected by fast cavalry rules. Flyers going to M10 and marching for 20 will hurt, but supposedly you can make a LD test to march even when blocked, which cold-blooded will help with. They'll probably be a little bit clunkier to use, but will still serve more or less the same purpose -- a much more important one in the new shooting/warmachine friendly environment.
Ancient Stegadon
Everything I said about the normal stegadon, except replace "bolt thrower on top" with "blowpipe cloud on top".
Razordons
Always had a funny relationship with these guys -- never could make them work better for me than the entry I'm saving for next *grin*. Same caveats apply for all shooting in that the new LOS rules will make them a bit stronger, and the cover won't hit them as hard due to the long list of modifiers they ignore. Skirmishing rules are bound to affect hunting packs oddly, also. I guess they'll be a bit better, but won't hold a candle to--
Salamanders
I'm almost afraid to talk about these guys. The FAQs aren't supposed to have any real tweaks in them, but I don't want to jinx it *grin*. Seriously, no partials on templates combined with a heavily big-block friendly environment is going to make these guys straight-up amazing, and you'll be able to field more than ever. I guarantee every game I'm going to field every Salamander model I have. I was meh on the breath template until I tried them -- even under 7th rules you can score six or seven hits and ten to twelve partials with average placement and scatter, dealing S3 double AP panic-causing hits; in 8th that's just going to be flat twenty hits, and with larger units it won't be too hard to drop thirty.
Per salamander. Seriously, if they don't change this in the FAQ it's going to roll over cheap hordes, and might actually save us a bit vs. warmachines (I will discuss that shortly).
Yes they are awesome but there is the antispam rumor that states you cannot take more than 2 of the same rare or 3 of the same special choice, meaning only 2 units of salamanders
Saurus Scar-Vet
Kind of our poster child, an expensive but durable brawler that can tangle with a lot of lords on his own. Never got the charge without magical aid and never went first anyway, but units getting to attack back after being slain will see his T5 come into play a little more. Biggest change is now if you have the points you can put one dry in every block without wasting slots -- a huge boon for Saurus armies who needed the hero slots for harassers already. Not really better or worse, but easier to get and has always been strong.
Skink chief
Man, I love these guys, and now you'll be able to bring
several of them if you choose. High I actually matters now, and generally solid overall statline matters more in an environment not so biased towards offense. Parking these guys in Skink blocks will add killing power and help them hold, bringing them in skirmisher sets will add sniping options, and mounting on terradon and bringing with terradon units will give them killy power. Basically the same as now, but you don't have to worry about only being able to take a couple -- you can stick these guys just about
everywhere if you are so inclined. Note that the steggie lance on ancient setup is going to take a huge hit in that they aren't going to autobreak and you'll get full attacks back, putting the chief in danger, but in my experience the 2d6+1 impact and attacks from the chief can outright obliterate a lot of targets. Choose your battles. Oh, and from Stegadon above, watch out for warmachines, as they will ruin your day. On a related note, BSBs on large targets supposedly have an 18" radius now -- that's asking for trouble from shooting but that could be a strong argument for letting the toad handle magic and letting the Chief handle the troops *grin*.
Skink priest
Here is where things start to get interesting. Skink priests, limited by their lore in 7th, have always been pretty so-so, but if the lores are getting beefed up as much as it sounds like they're going to be pretty strong. The removal of a dice cap will help them cast even large spells. And, similarly to above, percents instead of slots means squeezing one of these guys in where before you needed the slots for leaders and harassers. EotG will be of relatively less value, getting you +1 to cast for the skink instead of +1 PD/DD, and a bad bet anyway b/c of new warmachine rules. Much riskier for less payoff -- although if the lores are as great as people are acting like even a small chance to get a better spell off could be good, and you can mitigate for warmachines. Just be aware.
Saurus Oldblood
Another really interesting result of the new percent system. What with mage-priests being such a good value for their points, there are a lot of times (2k points being one of them) where you can sneak an oldblood on foot into a saurus block for even more dangerous frontage. Blade of Realities probably won't be as important with monsters and megaheroes taking a hit, so fielding him for cheap might be a viable option. The carnosaur, unfortunately, is going to see rough times -- you can no longer screen him or even hide behind a wood (!) meaning he's going to get shot full of holes. If you can somehow account for that, he'll be strong, but suffer from the same problems as cavalry and other monsters -- ranks won't break and you won't get a flank bonus, in addition to eating full return attacks. Not as severe as a Stegadon, as both mount and rider are pretty durable here, but more of a support role -- and maybe that's how it should be. Carnie needs testing, on foot in blocks rocks, next.
Slann Mage-Priest
Here it is, guys. Mage priests define our army and our magic phase. Back when we started hearing about our 7th ed. book and people decided they hated the new Slann, I told everyone who would listen that when they beefed the lores in 8th we'd be in a better position than anyone to take advantage of it. Well, Christmas is here *grin*. It's going to get harder to brute-force single spells through in 8th, but mages who can consistently cast several spells will benefit largely, and we're certainly in that category. Mage spam isn't as strong compared to one strong mage due to set PD and caster level bonus, and that's again in our favor. Everything I've heard and the few spells that have been mentioned point to magic being huge. The new limited PD pool makes Focused Rumination relatively better as a cheap way to get 4-5 extra power die, seriously stretching thin the opponents dispel die. Stone soul and cupped hands mitigate the new (horrible sounding) miscast chart. Basically, we've always been masters of the BRB lores, and the new BRB lores are pretty stout.
That said, there are a couple of caveats. I've heard Slann may not get a Look Out, Sir!, which is going to be horrible in an era of no-guess cannons/stonethrowers and templates with no partial hits, meaning Divine Plaque of Protection might become mandatory. You have to specify your lore in your army list now, removing the reactionary flexibility of magic. And EotG support is going to be rarer. But all in all, we're getting a sweet deal, here, and I'm
extremely eager to see the new spells.
Special Characters
Kroak is going to be amazing at getting off Deliverance of Itza on a 5+ with a +4 bonus. Mazdamundi is going to be a BSB with an 18" range and not as fragile as your normal stegadon mount. Tetto'eko might actually be able to cast Comet of Cassandora now, assuming it still exists. That's all I can really think of.
Whew, that was long. Anyway, start brainstorming, people! *grin*