Would Brown punch Leonard's lights out, or does he get hit with five punch combinations over and over?
Hmmmm, let's see. Brown was comprehensively schooled and beaten up by both Starling and McGirt. I'll go out on a HUGE limb and say Ray kicks his ass.
A case between a very good welterweight against one of the best welterweights ever. And the very good one doesn't have any particular stylistic advantages to make it extra tough. Leonard stops him in the mid rounds. A much more fair matchup is Brown against the more recent Sugar, in Shane.
Bad matchup for Brown... He does literally nothing better than Leonard... He gamely gets picked apart and stopped later on