You obviously rate him pretty high, anto, however I just don't see it. Zmuda had his limitations from what I've seen from him and pace is one of them. I don't think he was particularly great in the air either, considering his height, nor particularly good on the ball.
Don't get me wrong he's a top defender, but in terms of all time pool I can think of many others that would come on top if we're to get the best CB's in history.
He was strong, and by that I mean very strong, excellent organizer and read the game pretty well - of course these qualities are well appreciated and he didn't rely purely on the physical aspect of the game, but to me he's around Puyol level, who, is entirely different defender and I'm not fond of him either, but his leadership and organizational qualities with a great all rounder in Nesta is a pretty good fit in terms of CB pair.