If Dwarfs should have an identity of their own a theme if you will that defines the whole army it should be like a Mountain. The dwarfs shouldnīt really have any fast attack units not as such, in combat average they arenīt particularly awesome in close combat and their shooting while good isnīt the greatest of all armies but not the worst either.
Where the dwarfs strength should be, should be with their Toughness, Armor Saves and Leadership.
Basically any enemy that goes into close combat with the Dwarfs wonīt lose to them because of the dwarfs superior strength or anything like that, but because fighting them is like fighting a rock with a hammer or and axe, continue to chip at it might eventually wear it down, but itīs going to be hard work and this rock is fighting back.
Thatīs what I would want the dwarfs to be a really hard army not particularly fast or anything like that, but with more then enough toughness, armorsaves and leadership to make up for that.
As for new units besides the regular ones (i think we can safely assume that all of those units made out resin isnīt going to be replaced anytime soon) maybe a huge warmachine like that big cannon or something like that in the start dwarf stronghold in warhammer online.
A Golem would be nice, but i think it should be technical like its a special suit of armor either powered through steam or with special runes, not a living being as such (like the ones in Dragon Age) the golems shouldnīt be fast not as such it can deliver a punch sure but again like the other dwarfs its strength should be with its high toughness, leadership and armor saves.
Other then that i donīt really think the dwarfs needs new units as such what they really need is more of an update on their current units making all of them useful.
Ironbreakers are fine as they are maybe a little cheaper and give them something that really makes them this almost impenetrable wall of gromril that really can hold up a giant unit or two in 3 or 4 rounds.
Increase the Flame Cannonīs range so that combined with other warmachines it comes to its true potential as a warmachine that makes enemy units break and run for the hills.
Increase the toughness of Slayers these guys are or where our monster hunters they could take most of the high strength units and kick their ass the biggest problem (at least when i used them) is that most armies that has shooting can take these guys down before they ever get a chance to get into close combat.
If Slayers are going to become worth their points once again they need to be able to make up for lack of armor so that they actually have a chance of getting into close combat with a monster without being shoot to hell.
Oh and it wouldnīt be so bad if they could also make sure that the boxes our miniatures came in contained a little more units, currently a normal box of dwarf warriors contain around 16 units that great for when the main strength of the army still lay with the heroes and lords of the different armies but with the much more emphasis on hordes (in the new rulebook) i wouldnīt mind if there was maybe 4 or 5 even 10 in certain chases more units in each box, so that every box of plastic units contained around 20 units instead of the usual 10 to 16 units per box.
From a buisness standpoint i can certainly see the logic in making the costumers buy an extra box to get those 40 unit of Dwarf warriors, but from a customer standpoint coupled with GWs ever increasing prices its getting a little expensive in the end.