I think a move to 147 would be a disaster right now. Say what you want but he IS chinny, yes he's been caught with some good shots but his legs go as soon as he's caught. Khan needs to change his style of fighting. He was more defensive at first with Roach, but the limelight and the praise have gone to his head, now he comes out swinging and pays the price.
The catch 22 for Khan is that his exciting style is what makes him popular and sells tickets, but it's also what gets him knocked out. As much as I'd like to think he'll learn from the Garcia defeat, he seems to think it was a fluke / off night, rather than fundamental flaws in his game. Until he really has an honest look at himself, he's destined to make the same mistakes.