Dana's main reason for unifying the belts is to rub the demise of Pride in Nobuyuki Sakakibara's face because of his distain for him. When Zuffa purchased Pride, the only intent they had was to get their video library, so they could use the footage in their promos, and fold the orginization. The orginal purchase price for Pride was around $60 million dollars, but when all was said and done, Zuffa paid around $13 million for it, which is what the video library was worth.
I may sound bias because I work for one of the UFC's rival promotions, but the UFC really is not the be all, end all in the world of MMA. When you check out some of the other promotions, like King Of The Cage (plug plug), you will see that shows like us will give you more for your money than the UFC.
BTW, I think Rampage will win in September.