People have been calling for his move to MW for a while. He was a bit undersized at LHW. Now he's more of an average-sized MW.
I imagine, as a career move, he thought he'd win more fights there. Certainly, there are fewer knockout artists and overwhelming wrestlers at that weight class. I'm sure Silva's loss probably contributed, but I don't think it was the primary reason.
Lyoto never should of been a lhw he is the second best outside of the 6'4'' super freaks he just can't match then at 205 but if he bulked or they came to 185 he'd rule he will be the new Silva like I think shotto box planned it. maybe even a rematch at 185 with shogun him moving to 185 means shits geting real for him.
I think he did it because Anderson Silva lost the belt and didn't really want to fight for it anymore, plus There's alot going on in the LHW division, jones is fighting glover, then he'll probably fight gustaffson or the winner of cormier vs evans, like I said there's alot going on and machida would have probably had to wait a while for a title shot and if he manages to become the MW champ he might have a superfight with jones at LHW, either that or he just doesn't want to fight jon jones, but I doubt that's the case