Off the top of my head (might forget a few)...
1. Appraisal system is GONE.
2. Less level grinding
3. Party money is pooled instead of that crappy discrete money system
4. None of that confusing, annoying multi-random dungeon entrance stuff. Every labyrinth's entrances and exits stay the same.
5. Class is tied to races
6. Main story arc is more engaging
7. Graphics are a bit better
8. Indoor and outdoor labyrinths (1 is quite claustrophobic)
9. Alchemy instructor is much sexier
Basically, they took almost everything there was to hate about CoH1 (there was a lot) and removed or improved it. As a result, CoH2 is a much more enjoyable experience.
CoH2 gives you a bonus if you import your CoH1 save at the beginning, but I wouldn't recommend playing CoH1 if you haven't. It's just too abusive and might turn you off of CoH2 before you even start.
Item number 1 already makes COH 2 a better game than the first one. That was one feature I could have lived without as it was quite tedious. Thanks for the list. All of this stuff looks pretty good!