An epic RPG has it all good combat system, grouping, story line etc and IMO BG2 was the last one of those.

Theres been a couple of good ones since, KoToR ( the first one the second one was shit) and vampire :TM come to mind as being almost there and oblivion wasn't bad.

The orginal NWN was more of a RPG tool, i guess if you got into the expansions and user made stuff it might have been ok but i played it for about a week and was sorely disappointed.

If they've actualy added some worth while content i might give it a look tho.