Tmac is not the player to build your team around at all. He's injured far too often to be a dependable all-star. I'd find a team that is a superstar away from playoff contention to trade him to and find some young, HEALTHY players to put around Yao.
T-Mac is injured often yes, but they're not major. He's certainly no Penny Hardaway or Grant Hill, sitting there stealing cash. Despite playing with an injured back, T-Mac is still considered one of the league's best. He is the Rockets most valuable player, and his presence in the lineup certainly reflect in the Rockets record when Mcgrady's playing.
they just throw the ball to tmac or Yao and watch them go
It works, and plus, better throwing the ball to T-Mac and Yao rather than Ryan Bowen Rafer Alston, Derek Anderson, & Juwan Howard.
especially when tmac is injured half the season every season
http://www.nba.com/playerfile/tracy_mcgrady/index.html
Most game he's ever missed in a season was in his sophomore year with the Raptors, and that was 33 games. That's still not half.
In fact, MJ missed more than 60 games in 2 different seasons in his career.