Rebuilding is a strong word. It would mess things up worse if you think about it. UFC 3 revamped the striking, UFC 4 revamped the clinch,takedowns,GnP. I highly doubt they can revamp the whole game for UFC 5 and if they did , it would result in a new "UFC 1" where the game is completely brand new , but shallow. UFC 3 was the beginning of the franchise for me. UFC 1 & 2 were the stepping stones for 3 , as it moved for an arcadey game to a simulation game.