I always felt they had some very good humor - not only in PS:T, but also games like Baldurs Gate 1-2 had decent humor(Minsc and Boo anyone? Characters like Korgan and Edwin are also examples of great writing).
The thing about KotOR2 is that it was the first game for Obsidian after they launched, and they needed to publish something that would sell well in order to get enough cash to be solid. Remember, Black Isle may have produced some of the best RPGs ever(BG games, Fallout, PS:T, Icewind Dale etc), but they went out of business because they didn't have enough money in the end.
I have high hopes for NWN2 now that Obsidian finally has enough money to make thorough games, and also for a game in production they won't reveal anything else about than "it will remind you of Baldurs Gate" or "modern Baldurs Gate" or some similar quote.
Avantenor is right though, this is not really something to discuss. Bethesda will make FO3, so let's hope for the best. Also, if it has modding capabilities like Oblivion, the old hardcore FO community will surely make mods to remove the "childfriendly" feeling of ES:O.