Yao is going nowhere for 2 reasons:
1. most important reason --$$$$$$. He makes Houston way too much money from Marketing to even think of moving him. $17 million a year for this guy may seem like a lot when compared to other superstar contracts but he brings in more money than just about anyone else. He's a bargain for Houston when marketing $ is considered.
2. He's not that overrated. Health issues? absolutely. Skilled big man. Definitely. When healthy he's one of the top few centers in a league with a severe lack of true centers, nevermind centers that can both score AND defend. He can do both pretty well. Keeping him on the court has always been the issue with him.
Mcgrady is the piece to move but he's not going to get them much-->always hurt, skills in decline, never won anything wherever he played, me-first attitude (by reputation). He could help a 2nd tier team possibly push to contender status if he could stay healthy (possibly Utah--could use a go to crunch scorer on the wing) and buy into a team concept.