1.THAC0 is gone. I haven´t had the time to investigate this matter but I know that it´s gone.
2.Armor class is better when the number is LARGER. So 2 is better than 1.
3.You can create multi-classes just the way you want.Druids,paladins and ranger can now be multi-classed as well.But...if your race has a favored class then you suffer experience penalty if you don´t have his favored class and the classes are more than 1 level apart.
Like this: Aasimars favored class is paladin. If you are rogue lvl2/paladin lvl 10 there is no experience penalty. If you are rogue lvl2/mage lvl4 there is experience penalty. Humans and half-elves DO NOT suffer experience penalty at any case.
4.Druids can shapeshift to many animal forms like a boar or winter wolf. The whole shapeshift arsenal can be found at Icebounds updatet class pages. I haven´t found any certain info about lychantropy...I hope it´s in the game cos´ greater werewolf ate my heart.
5.There are no NPCs to join the party.You create it yourself.
6.ID2 is BIG. Much bigger than ID and HoW...that´s what they say.
7.There are 2 sub-classes for every race.Including DROW
8.You can find very very much info about 3e rules if you go to Icebound (easily found from Black Isle ID2 page) and from there go to D&D 3e rules. This info might not link to ID2 but it´s very interesting (they have werewolves,weretigers and bunch of other stuff).
This isn´t much but I hope it helps someone. While some of you might think this thread stupid I disagree. Some people have limited time to surf the net and to find a summary of detailed info is a savior of the day. And there are people checking these boards to gain info but they don´t write threads. I did that 2 years ago and when all the info was scattered around in hundreds of threads I registered as a member. Hard time surfing in millions of sites is still necessary...