For MtGox we wait for the situation to normalize, one week without bad news hitting them would be already a world record!
How does the bad news affect your decision to include or exclude MtGox to your trading platform?
I thought markets are heading to the direction where MtGox is heading. And if bad news hits MtGox, it affects all the other exchanges accordingly. Excluding MtGox from your trading platform decreases liquidity and volume. If you mean different kind of news or situation, please explain that.
As far as I have understood the announcement, Bitfinex people try to expose only a fraction of our (user's) USD to the risk of being locked into Mt.Gox. Please recall: even if some USD show up within your Bitfinex trading account, in reality the corresponding sum might be in the Mt.Gox account, or in the Bitstamp account, or at the Bitfinex banking account.
Thus if everyone rushes to exploit the arbitrage possibility, a lot of BTC will be sold on Mt.Gox, causing a huge fraction of user's overall USD to end up within the Mt.Gox account. Now consider what happens when tomorrow Someone
(TM) just decides to freeze the banking account of Mt.Gox.
Compared to even the
mere risk of such a happening, any considerations regarding rates and liquidity and volume seem secondary concerns. Thus, personally I think Bitfinex people acted in a quite responsible manner.