Is there a list of the balance changes introduced by RotE? I'd really appreciate, if someone posted a link to it. There seems to be a lot of these, so I'm interested in the details.

I don't think unit stats changed at all. The only thing that changed was that parties now heal 10% HP on home terrain. This change makes level 1 towns good for nothing more than spell cover.

From what I've played for just a few missions, the Witch Hunter had his health boosted from 125 HP to 140 HP, Death had its Initiative lowered from 60 or 70 to 40 and I think the Necromancer got a Death Ward. I doubt that's all. So there were quite a few changes.