BJ could still beat more then half the current WWs in the UFC and even a higher % of the LWs, so no she should not be cut but maybe accept/choose fights more wisely. Having said that, we all know BJ backs down from no fight b/c that is just who he is. The UFC brass could however be smart about it and only offer fights that make since but do we really think that is their priority?.....
Not sure if I agree with your "percentages", but the smartest thing the UFC could do is convince BJ to fight at LW, and give him 2-3 middle of the road fights, hope he returns to his former self, and market a title fight (although he'd likely get stomped on).
If they got him to return to lightweight, and give him somebody like Pettis, and then a top 10 guy like dos anjos, cerrone or alvarez and he wins, they could possibly sell a LW title fight. Otherwise I have no idea what BJ is doing, other then collecting paychecks and getting thrashed in a division he shouldn't be in. I'd rather see him gatekeep in the division where he was once a champion, not get wrecked in a division that he will never accomplish anything in.