Doom3 is a wonderful graphics engine. They should make a game out of it.
Honestly though, it's a good game... the first time through. But there's really absolutely no replay value. RTW, however, has a LOT of replay value (especially if you dont cheat and unlock all the factions at the very start).
Bugs? Daggerfall is most likely the single most buggiest game ever, and it still is my favorite game. Why? Replay value and gameplay. Sure, it crashes every thirty minutes on average, but who cares? I'm having fun, and that's what is important.