Bro, Canelo weighed in at 165 at fight night when he faced Mayweather. He was 13 pounds more than Mayweather, it has nothing to do with Mayweather not wanting to fight him at 154. Mayweather is just stylistically very good against opponents that are aggressive, come forward and who he can read, and Canelo was just exactly that. The reason he won't fight Manny is because Manny is such an unorthodox type of fighter it makes him difficult to read(Marquez being the exception). He wouldn't be able to slip and read the direction of Pacquaio's punches, since Pacquaio Punches at unpredictable angles. That is the real truth why he doesn't want to fight him. But other than Manny their isn't anyone in the welterweight division who has the level of master craftsmanship of boxing technique that can take him on. Yes you can argue that Sergio Martinez could beat him at welterweight if he came down to fight him, but a lot of Sergio's power would be gone since he would be weight drained in my opinion.
Also Silva was a truly great champion, and my prayers go out to him and his family and hopefully he will make a speedy recovery. Chris Weidman on the other hand is a very good combatant who has earned my respect, and I wish the man future success in the octagon.