Nobody in their right minds would aquire McGrady as a core piece of their team. And Vince Carter has twice as much value as McGrady at this point.
McGrady is an expiring contract. It might be all the Nets can get for Vince, and New Jersey had some interest in an expiring contract for Vince at the trading deadline. If Houston can add a prospect to the mix, or a draft pick, then the deal becomes quite interesting for NJ.
NJ had trouble trading Carter because he had poor trade value, mainly due to his age and having a contract that stretched past 2010, which meant only a limited number of teams were interested in him.
From a talent standpoint, it's highway robbery.