there has never been and there will never be, most likely, a player who is world-class at everything - even the best CB out there have weaknesses about their game. What makes a great player/CB is improving on your "soft spots" and limiting their influence on your game, as well as playing - and making the opponent play - to your strengths, as opposed to make use of your weaknesses.
Vidic, for one, may be a better header of the ball due to his more imposing physique, but he has his limitations in other areas. Same goes for virtually all defenders out there, active or retired.
TS may not be the best at defending crosses out there, but he is far from the worst and it's not exactly a weakness in his game. IMO, he is very good in some aspects, while great in others, and poor in none, which makes him a very balanced defender, who I personally wouldn't replace with any of the currently active defenders out there today.
There certainly are defenders I'd would take over him but they are either already retired - Maldini, Cannavaro - or are about to, like Nesta, for instance.