I think 8th ed is a great set of rules. However, I don't think there is anything in the new rules that benefits VCs (unlike almost all the armies) and in fact, lots of the changes undermines the strengths of VCs so that it isn't broken like TKs (who will be getting a new book soon anyway) but leave it mediocre. That isn't to say that a skilled player still can't win games (as I am a skilled player and I know I will win games) but that the army book doesn't give you any particular advantages.
My fear is that VCs will become the Necrons of WHB - awesome for their brief time in the sun but soon outclassed by almost everything else. Am I being overly pessimistic? Are there other armies that don't get anything from the new rules too (I'm guessing Brettonians might feel the same except for big increase to magic defence)?
P.S. My reasons for my opinion are as follows.
Magic
VCs rely on magic so more random amounts of power dice make it much harder to have a reliable strategy.
Using one die to cast spells will pretty much go the way of the dodo because being unable to cast any more spells will cripple your army
Having only one spellcaster with any given spell makes it harder for an army that relies on magic so heavily and almost makes necromancers redundant
Dispel dice are much more easily available and for some armies (like Orcs) they can utterly shut down your magic phase which is sure fire death for VCs
Combat
VCs rely on a war of attrition and combats are much more lethal now, meaning more casualties. VC units don't hit anywhere as hard as any other army in the game so now units are going to get mauled more often (and makes units like Chaos Warriors all but unkillable).
Combats always going with I affects VCs badly because of their terrible I.
Both the above effects have impact on crumbling (more attacks before I strike means more casualties and more models dying) and magic (now I don't have the magical power to restore units hammered in combat).
VC units are either too expensive or too useless to bother going horde sized for what they can do.
No more autobreaking and +1 combat res for fear is nowhere near a good a replacement effect.