Aside from what desoe said, which i agree with, i would add that if we had Pique/Puyol and Chyg/Milito it would give us a double CB pairing who are in terms of their physical characteristics and their playing style complementary to each other. This would be ideal for injuries, suspensions and rotation. Of course we would have other options too, if all our CBs are injured we have (god forbid) Abidal to play as a CB and also Yaya (if he doesn't leave). No matter about that - a tall short, tall short - or passive combative, passive combative selection of 4 is great, and better than having 3 talls and being forced to play Chyg and Marquez together eeek!
I do wonder what will happen to Henrique though, for example. I mean he hasn't been bad for Racing though Racing are quite crap which isn't great news.