Hodir: just normal destruction is fine, I don't think you'll get that much more (if at all) by going shadowbolt.
Vezax: Probably something like this:
http://talent.mmo-champion.com/?warl...0&version=9947
Its basically a demonology build which uses the imp, without the felguard and mana feed. The reason for this being that the imp benefits from standing in a crash (!) and regens mana normally . Also, this means that you can use the shadowbolt glyph and soul fire (cheap spell, mana wise! (9% base mana, compared to 17% for shadow bolt and 14% for incinerate, 7% chaos bolt, 17% immolate)).
tbh, I got a vezax hard mode kill (25 man) being just destruction with a twist. (took points from the mana regeneration and put them in affliction / improved curse of weakness because our arms warrior complained he couldn't get the 5 points in improved demoralizing shout and reach his 'must have' talent points). Wanded the last bit of vezax down

.