If you are wondering, I restarted on Hardcore and I've noticed the following changes.
More Skill Points per level. It's sort of 1.5, it seems that one character gets 2 for a few levels and then the other get's two.
Poison is more powerful, and the monster do a little bit more damage. The spiders on the Battlefields surface do serious poison damage. I don't think they were that bad before, but I have visited at a lower level so maybe I'm imagining it. On the other hand the skeleton mages seem pretty wimpy but the first time on tactical they gave me grief. So maybe magic is the same and poison is beefed up. Hard to say.
More monsters. The ghosts that were locked in the prison cells near the thirsty prisoner. Well there are two per cell instead of one, and one of them seems to increase level to match your party. He was level 9 when I fought him and pretty hard.
