Diablo 3 Wizard - Nightmare Notes on Bastion Keep and Heaven

I've seen statements that you should be able to end Nightmare Level at level 50, but I think this is true ONLY if you're using a toon that's very well geared (and it's more likely on Barbarian or Monk simply because they're the toughest characters.  Wizards have about all the durability of wet tissue paper.)

At Nightmare level in Diablo 3, wizards are very crunchy targets and apparently number one on the diet of every bad guy out there.  After surviving the interior keep, I was fairly certain that I could handle the battlefields -- they hadn't been THAT much more difficult in Normal mode, and by now I was level 49.  Just charge in, throw the Templar at them, and it'd be great.

Boy, was that the wrong assumption. 

I found that I needed to upgrade my gear (via auction house) AND the Templar's gear to at least level 45 to get through there without dying every two minutes -- instead, I died every three minutes.  Switching to Frost Build also helped.  After trying all three followers, I found that the Scoundrel seemed to work better for a lot of the battlements and the Enchantress worked better in the battlefields.  However, once we got to the "heart of sin" part of the quest, the Enchantress proved less than successful and the Templar turned out to be a better choice.