I have got to say that I could be standing next to that man in the city and I would never recognize him as Osama. Amazing. I never realized how much I tied his looks into his turban and beard.
I wouldn't recognize him, either. If he can gain weight, that's all he needs to do besides shave and dress modern.
He's tall, but if chunkier, carrying a briefcase on a subway in NYC while wearing a three-piece suit, who would know it's OBL?