Currently, the 185 pound division is a bit of a wasteland. Anderson Silva reigns on top, and is so far above everyone else that we have to see meaningless fights like his fight against Thales Leites in April. Anyone has a chance, but nobody would try to claim this is a legitimate or compelling title fight.
The same thing will happen to the welterweight division if (when) GSP defeats Thiago Alves. At that point, there will only be rematches with guys Georges dominated, and first time fights against guys like Jake Shields that are such mismatches that they border on being sick jokes.
For the sake of saving both divisions, St. Pierre's future is at 185 pounds. I know he trains with a lot of guys at 185, but I think he can be convinced. At 185 pounds, he would really open up both divisions. He should leave his title behind and go to middleweight, and allow a new 170 king to be crowned.
At 185 pounds, the interesting matches abound. Rich Franklin, Dan Henderson, Michael Bisping, Wanderlei Silva, Anderson Silva...what fan wouldn't love to see GSP fight these men?
Georges always talks about how he needs a challenge to stay motivated, and this is the right challenge for him going forward. He would need to build muscle and take the time to do it right, as he said last night in the post-show press conference, but this is a guy that takes down Rashad Evans at will.
Usually people suggest weight changes because a guy loses, but in St. Pierre's case, it's because he's too good.