I'd love to see Cassano at Juve but age is a factor here. Some players at his position really tend to play in the highest level till their middle thirties like DP, but more common are the cases when they drop their level years earlier. Raul for example didn't even reach 30 when he already was considered old and you can't blame him, at 29 he already had 12 years behind him as pro footballer and his legs just started to give up after all the kicking they'd been through. It's a demanding position to be the leader of attack and receive foul after foul and be marked by several guys constantly. We can't know about the Cassano case, but I'll be really surprised if he really had those 5 prime seasons ahead of him.