Money stuck in exchanges keeps the Bitcoin price artificially high. If Mt.Gox ever processes all withdrawals, more people will convert to fiat to get their money out. So prepare for a price drop when they do.
It might also increase trust in bitcoin and the ecosystem, which could lead to another run-up.
Mt. Gox is almost irrelevant to Bitcoin at this point. Since they're not paying out USD (at all) or EUR (much), and only an idiot would deposit there, most of the "volume" there has to be the same money sloshing back and forth within Mt. Gox.