I agree with what Brian has said.

The idea that good teams should be forced to DROP good players because noone will trade with them is silly. Unless you get a top 5 pick, the player you get in the first round of FA will be of significantly less value than the 5.000 PB value player you traded for a FA pick.

Furthermore, this notion adds to the myth that older players have no value, which further depresses their value. And if aging veterans with good numbers have depressed trade value on the free market then it hurts rebuilding teams as much (more) than it hurts the truly powerful teams.

As a side note I always find it funny when people think player X is worth a 1st round pick if they are selling... but is only worth a 3rd round pick if they are buying.

Or... a 35 year old star is worth two 25 year old budding stars when you are selling .... but isn't worth a 1st round FA if you are buying.