think about it
Why do they delay?
To make the game even more perfect.
Think for a moment. They released the previous one with minimal delay, and they ended up with one, count 'em, one glitch, which you have to use a cheat to aquire. They also maintained one of the best most played games for years with little delay.
If this Brawl has proportions to melee in comparision to developement time to awesomeness ratio then just think of how mind blowing the final product will be.