He is not a very great player, and he is not young either. He's not better than Nedved and he would just add an impediment to younger players developing.
Nobody ever calls him "Bob" Carlos. It struck me as funny... I mean his name is not actually Robert, it's Roberto, I suppose it'd have been more funny if you said, "Bobo Carlos"...
Aimar isn't going to solve any of our immediate problems, he is niether a left back nor a young center back. He will however, be a great longterm replacement for Neddy.