We'll never get him but the clear answer is McGrady. The addition of McGrady allows you to move Jim Jackson to the 2 with Taylor and Nachbar off of the bench. If you could get Brent Barry for a PG, you'd have 3 tall perimeter players with range and each is a good passer. Cato and Taylor are good enough if surrounded by Yao, TMac, JJ, and Brent Barry. Yao's biggest weakness is lateral mobility so incoming players need to be tall, athletic and mobile. That's at least 2 strikes on Brand.
Agree with Yao's biggest weakness. But I think you are a bit harsh on Brand. Granted he isn't tall for his position at 6'8" but he "plays" tall. He has long arms and can defend. I also feel he is relatively athletic and mobile. He is not as mobile as Stromile Swift for example but he is still pretty mobile. I really think you are selling him short.