There's already 3 vying for a spot now and another will no doubt crop their head out in a fight or two. FW actually needs to kill a contender or two off.Why kill off a contender? 145 needs as many marketable contenders as possible.
This way is better. Creates lots of options. Let's say Aldo beats Lamas and then decides to move up to 155 (which is a possibility) and vacates the belt you can have a 4 man tourney for the belt between Swanson, Mendes, the BJ/Edgar winner, and Lamas since he shouldn't fall far after losing to the champ.
Or if Aldo beats Lamas (since it clearly seems he's getting the next shot) now Aldo can fight either Mendes or Swanson and the other fights the winner of BJ/Edgar.