QUOTE(ensane @ Jul 17 2013, 21:15)

Light armor is viable vs heavy, right? Also, changing to DW from mage and I'm wondering how to best use spells to help me now.
Just like with mage, you'll want to keep multiple buffs up on yourself. You aren't as squishy, so you may not need all the protective buffs all the time.
When I'm running Cold Mage, I usually keep all buffs up (Haste, Protection, Spark of Life, Shadow Veil, Regen, Arcane Focus, Spirit Shield and Absorb), simply because monsters hit so hard at high difficulty. Absorb and Spirit Shield are dropped when I go down to Hell from IWBTH. Debuff is only Imperil 95% of the time, with a Weaken or Silence thrown occasionally (or Sleep or Silence in Ring of Blood).
When I'm running 2H IWBTH, it's the same set of buffs, just with Heartseeker instead of AF. Go down a few levels and I drop Shadow Veil (costs too many MP) and Spirit Shield (unneeded below Nintendo with Heavy's defense). Given Heavy's defense, I rarely throw debuffs, usually a Weaken at particularly annoying Giants or a Silence on a Celestial that I know I can't kill before it fires a high power skill at me.
The most important buffs for a melee to have up are Haste, Regen and Protection. Heartseeker, once you have it is also huge (+25% damage = kill mobs in 80% of the turns = 20% less damage and time taken)
DW has a few options that 2H doesn't. Sleep is much more effective, since you won't Domino the mob and wake it up. I remember using that extensively when I was low level DW, and now we have 3x mob Sleep available at high levels. Weaken is still very good at crowd control, and has the advantage of a much lower cooldown. If you aren't using a weapon that procs PA, then Imperil can be a useful spell as well at higher levels, since it strips physical defenses as well as magical ones. Generally DW will put a Rapier in offhand to dish out PA anyway, but until you pick up a good Rapier (good Balance Rapiers are expensive) Imperil will do the job just fine.