For those willing to wait, this should temporarily make arbitrage more profitable. People that cannot wait 2 weeks for withdrawals will have to use their USD balances at Mt Gox to (re)purchase Bitcoins, which can then be moved to other exchanges and sold. This will cause a temporary, artificial increase in demand at Mt Gox only, leading to a higher-than-normal price differential between it and other exchanges.
That said, this is only the latest snafu with these guys. I am tired of all of the issues at Mt. Gox. Someone else really needs to step up in their place.