He has brittle hands so he cannot let them fly. Thus he does what he can with the tools at his disposal. What Floyd has better than any active fighter is his timing which is orders of magnitude better than everyone. That alone is enough of an advantage to overcome his brittle hands. Hell, I'm by no stretch a Floyd fan but damn... to imply he has a weak offense is ******ed. In fact it would be obvious to most that Floyd has just enough power to make ppl think twice about going off with a flurry after they have gotten a taste of getting timed to death. Then the opponent gets timid, like Canelo did and just stand there frozen, much like how Tyson used to freeze ppl with his twitchy head movement/feinting.
Mayweathers offense is far from average...he has pinpoint accuracy, his right hand is sneaky and demoralizes his opponents when they keep getting tagged by it. He is not a combination puncher but you can't win fights with defense alone. To say Mayweathers defense is average is pure ignorance