There seem to be a lot of casual boxing fans coming out of the wood works with absolutely no idea about the sport. Floyd will not KO Khan within the first 2-3 rounds, Floyd does not KO anyone within the first 2-3 rounds, that is not how Floyd fights nor has he ever fought like that.
Amir Khan in absolutely no way deserves the fight, this is a fact. There are many fighters out there who have more claim to fighting Mayweather but unless Mayweather fights bigger opponents at higher weight classes, there are very few out there that would trouble him more then Khan. Mayweather would outbox Maidana and Garcia blindfolded, both of those fighters would probably KO Khan within 6 rounds if they fought again, but styles make fights. Mayweather would have never fought anyone as fast as Khan, and Khan would be up against someone who is NOT a big puncher/one punch KO fighter, that is his biggest weakness.
I hope this fight is made because in terms of class, we know Mayweather is leagues ahead but that doesn't mean he would KO Khan within 2-3 rounds. It would be very interesting to see how Mayweather adjusts (which I believe he will) to someone as quick as Khan. It would be extremely boring watching him outbox Garcia or Maidana because he's just done that to Guerrero and Canelo and made it look easy.