It is what it is. UFC has a 135lb division. If Cyborg and her man muscles can't get to 135 then so be it.
Guy fighters don't even make catch weights out of rivalry. UFC couldn't get Anderson and GSP in there after 2 or 3 years of talk. Don't see why Ronda would fight her at 140.
Ronda can fight Liz Carmouches of the world and the division can die out rather soon.