The reason this weight worked for Marquez is that Pac is not a natural light welter and obviously they had issues to resolve.Marquez should stay at lightweight and Khan should stop calling out Mexican legends who are past their prime and even futher past their best weight.Khan will become at least a light-middle with ease so why does he want to fight blown up feathers and super bantams.Fighting Marquez will prove nothing.
JMM would have a tougher time with Khan whose advantage will be length, speed and youth. Khan, if rumours are correct, has gotten the better of Pac in sparring which shows Khan is likely a more technical fighter than Pac. Boxers practice technique in sparring not the power shots which Pac relies on.
The only reason I want to see this is happen is so the fight can be staged over here in the UK. I'd love to see a JMM fight live.