The BF was not intended to play a big part in the story (I only used them for the merchants). With the concept of rifts, the existence of the BF could have been better integrated into the main game, but the area itself was always meant to be an optional region you could visit for the traders and to gain experience. After DD some people wanted random regeneration of monsters for extra hack-and-slash, while others wanted to keep playing after the end of the game. The BF mostly satisfies those wishes, without making them mandatory.

The BF quests are rather simple. AFAIK the BFs took a little longer to implement than the Larians originally planned for. At one point during development they stated that the BF quests might not make it into the game. Hopefully if they are using this in DD2 they will have the time and resources to develop it more, so the quests are less cookie cutter hunt and fetch style. Then again, fans of action RPGs seem content with hunt and fetch quests, so as long as they are optional, their existence would not really detract from the main game.