In his field I'm sure but not yet a legend for me. Legends are people that the world will talk of in 100 years time.
For me that is Bradman, Ali, maybe Warne, Pele, maybe Messi, maybe Roger Bannister, maybe Bolt but not sure in 100 years time Mo will be talked of. That is no disrespect to him either but legend is a very exclusive club.
Possibly also people like Frosby (as in the Frosby flop in high jump) as innovators of sport who started to do things that everyone copied
I bet you are a riot at parties.