I think they did a darn good job working out their lore in DA. It's a bit more greety than Forgotten Realms I would say...
What was fun with Baldur's Gate is that they could tap at that 30+ years of books and pen & paper D&D. Boo wasn't just Minsc puppy, it was an actual creature spoken about in one of the D&D (the giant-miniature-space hamster, or something like that)... Who remember the encounter with Elminster ? Drizzt !?! These are decades-old heros of D&D lore. Each book, novel, game can tap to other events in other D&D material, that's part of the beauty of it.
Comparing DA lore to D&D lore is like comparing Willow (the movie) to Lord's of the ring... BUT, I think they do have all the things at the right place to provide the firm grounding for a LOT of in-depth stories, lore, quests, creatures, politics, etc...
That being said, D&D lore encompass 100's if not thousands of books, games, pen & paper quests, novels, etc. Each game in the D&D world is just a tiny brick in the wall. The game come & go but the D&D world stays.
I'm really afraid DA world will last 1 or 2 more games and a couple of DLC's... in 2012 all shall be finished.
...then I'll mourn again, waiting 7 years for the next great single-player RPG game. And D&D games are such crap recently : great lore but such bad games. Tsk...