It appears that even though MtGox and Bitstamp have nearly decoupled, they are still very weakly correlated in directional bias.
I think it's quite obvious that MtGox is the main price driver at this point. The other exchanges may have decoupled but the state of MtGox and the question whether it will survive and withdrawals will be restored is still very important for the price at this moment. A higher Gox price will be associated with a higher chance of good news coming out of MtGox and this will cause other exchanges to rise as well with it.
What I have been pondering is whether this directional bias will also be the case if they reinstate withdrawals, or whether the surplus of BTC would drag down the other exchanges. I don't think this can be found out any other way than empirically, so I'm going to be watching very closely, because this will likely decide whether or not we have a longer term bear market. So far, Bitstamp looks strong to me.
I don't see why the freed bitcoin would cause more than a small glitch in the other exchanges. Bitstamp is closely linked to Coinbase, so I don't think that there will be a substantial lack of fiat.