I don't think his weight/size had much to do with his difficulties at WW.
That said, I could see him cutting to LW based off his frame. At MW he'll be much much smaller than the competition and likely not much faster either. I'd say switch camps, switch workouts, switch anything other than division.
"If it was old school MMA I would just take @bisping down and lay on him til he died of starvation."