Apparently Jeff's thinking about going back at some point and updating Avernum 1, porting it into the new engine and giving it the latest graphics and sounds. I hope he does, because as it currently stands I really can't play any of his earliest games for longer than five minutes... I honestly can't.
Yeah . . . unfortunately, though, when he "updated" Nethergate -- remember -- it was still that old clumsy interface where you were best off using the keyboard to move you character around, lest you bump into walls all the time . . . the old graphics and the old simplistic animation. But . . . obviously I can't really comment knowledgeably on his plans for A1-A3 since I've no idea what he plans to do with them.
Personally, if I were him I'd leave those games alone and put all my thought and time into to the next thing. But . . . duh, I'm not him.
Unfortunately, NwN1 is no longer on sale for the Mac. I'm sure you can find it used, though, so . . . no argument.
Same with Baldur's Gate too, I think -- though I could very well be wrong.
Of course: anyone who can't find them used and wants to buy them new can always partition their Mac with Boot Camp and install XP . . . which is what I did.