I like your initial idea-list.
3 Night Scythes, 3MSU troops with Stormteks for glance love, 2 beefed up squads of wraiths and zhandrekh.
Sounds good! But since we're talking about MSU troop squads why is the number 6 and why are they immortals? Really, when you look at it from a competitive point of view Immortals are not worth playing. Warriors are way better. Spam more warriors I say!
Since I never liked snipers and never used them I'm gonna tell you to replace them (however, I know they are perfectly viable) with a destroyer lord perhaps. The Anti-MC, anti-Deathstar unit you are now missing is swapped with the wraiths.
A Destroyer lord with a Warscythe, a SW and MSS leading 6 wraiths with 3 coils is completely and utterly wreckfacing(is there such a word?)
Not only does this unit have the same role as the Deathmarks, but it is better, more survivable and most important: It is versatile. It can complete all kinds of different roles(AI,AT..).
In some games, if you feel like it, you can even separate the D.Lord and roll him alone. He can solo pretty well.
After what I suggested: Dropping the Immortals for Warriors and the Deathmarks, I think the Annihilation Barges are also kings.
I've tried them out in 6th ed games and they are just so good you can't skip gettin 3 of them (unless you play with Scythes).
Something like:
1497
overlord, scythe, weave, mss
destroyer lord, weave, mss
stormtek, 8 warriors, night scythe
stormtek, 8 warriors, night scythe
stormtek, 8 warriors, night scythe
6 wraith, 4 coils
annihilation barge
annihilation barge
annihilation barge
I love this all comers list!
Crons: W? D? L?
I've lost count ! Who cares anyway? It's just a game...
Drop the warriors to 5 in each unit and buy the lord a chariot, much better
You have ruled this galaxy for ten thousand years
Yet have little of account to show for your efforts
Order. Unity. Obedience.
We taught the galaxy these things
And we shall do so again.
Pro-actively transhumanist and an Immortalist
The fable of the dragon tyrant explains why. Text. Youtube.
You and I have opportunity to create synergy
Most likely was going to stick him in a warrior squad for added survivability, basically in the unit that is going to take a far objective.
I've been reconsidering adding deathmarks back in because it seems every time they deepstrike, they can mark a new target, so they aren't as one-hit-wonder as I initially thought...
But that means major list restructuring. Again.