Why would big players move to Bitstamp? It has about 1/10th the bid depth as Gox. The "big" players cannot cashout without causing major slippage.
I think, most of bitcoin economic active passed through stamps, and so their is more market buys and sells, then bids/ask walls.
this is why the bid/ask depth looks like about 1/10th that of gox, yet volume is well over 1/4 gox
friends of Gox could be the whale