Okay, and why do you use MtGox still.
Decent APIs, only well functioning multi-currency exchange, very good arbitrage vs other exchanges and a deep order book. To sum it up: Profit.
The only profit you or anyone makes from the use of Mt.Gox arises from the gross disparity of information among its users regarding how to use it, resulting from Mt.Gox discriminatory customer service practices. There is no legitimate arbitrage opportunity arising from market forces (regional money flows imbalance ie. remittances disparity) or even 3rd party actions (taxation, regulation).
The only thing we are arbitraging is the severity of disparity of proprietary information among its users.There will always be some who dig deep into the APIs and the inner quirks on an exchange, and casual traders who either don't care or don't have time to learn it. And of course the devil often lies in the details. Like the 2.5% currency conversion fee when a order is matched against an order in another currency. Not many people understand how this works, even if it is accurately explained in the ToS and FAQ. There is extra profit to be made for those who do understand and know how to use it for one's own advantage. E.g. internal arbitrage, pocketing up to 2.5% - 2 x trade fees under certain market conditions. Most users are just not interested in those small details, and are just fine with trading BTC/USD all day long. The information is out there, but there is a disparity among the users who understand it, those who don't and those who simply don't care.
I don't agree there will never be arbitrage opportunities due to third party action. E.g. some US banks blocking transfers from MtGox even when acting as intermediate. When the money flow is hindered for a large number of users due to third party actions, imbalances will arise. Third parties can hinder the flow of information as well:
04:06 < x> MagicalTux: as a cusomer i think its time for a culture shift at your operation...more open communication with the community and the devels
04:07 <@MagicalTux> x, problem is that we still have some pending issues since early 2013 that hinder our communication efforts
04:30 < y> "some pending issues since early 2013 that hinder our communication efforts" translation: "we are under a gag order from US authorities"
I included the last quote even if it is speculation, but I think it is quite obvious by now that something like this is going on. I assume this is the reason why all attempts of legal action against MtGox have failed as well. The justice system can not force MtGox to do something which the government prevents them from doing. The case would have to be raised against the government, not MtGox.
There will always be various information sources as well. Some good, some bad, some ugly. Some ignored by most due to the sheer volume and detail, and not forget all the deliberate attempts to mislead the market with false information and speculation. IMHO the false information is the biggest problem here. Regulators don't seem to care about people who manipulate the Bitcoin market by spreading lies. In an open community like bitcoin there will always be sources of information which are open but which people don't connect directly to MtGox. E.g. if you want to have updates look on how the work on the new transaction hash is progressing, including comments from MtGox and other exchanges, you should go to
GitHub or follow the discussions among the developers in #bitcoin-dev and on the mailing lists. The process is in the open, but it is not obvious to all that this information is important or even relevant.