I'd rather see him back at lightweight. If he goes to 140 i'd only want to see him in against Hatton( Cause he deserves a good paday) or pac III ( for the ring belt and to finally settle the score)
Even 140 is too big for JMM, he should fight at 135. And for those people who say he could beat Khan easy are drunk, Khan is faster and has more of a reach than Mayweather. Khan would do a MAB on JMM he is too slow footed for Khan who would just fight at range coming in out fast.
JMM doesn't even look strong at 135 where Diaz physically bullied him and going life & death with Casamayor before the knockout. He should stay far away from 140 but chances are pride will be his downfall.