Even in spite of these issues, any of the exchanges should be able to pay out withdrawals with a short delay of well under 24 hours, just by aggregating the backlog into one single batch transaction and sending it out using the regular bitcoind software.
If I were operating an honest exchange and had a "spreadsheet" of bitcoin payments I needed to pay out, I would pay them all out in one giant "sendmany" transaction. Even if the transaction got mutated prior to confirmation, there is a 100% chance the transaction would go through. I'd repeat the same process daily or several times a day, and announce that only "instant" withdrawals are no longer available, they just have to be done in a batch, by hand, hopefully the same day.
I am guessing that even if the other exchanges must temporarily halt withdrawals, the honest ones will quickly find a way to get withdrawals pushed out with a 0-24 hour delay!
I am pretty critical of MtGox and stopped using them more than a year ago because I just don't trust them.
everyone always giving gox shit for putting a "bandaid" on everything and not fixing their problems. if they tried to appease people without fixing their internal issues or this mutation problem than then they'd get shit if something goes wrong with it later - regardless. i think them having a permenant solution or an internal workaround that solves this ISSUE once and for all is more important then just sending transactions out, dealing with all the "complaints" fake or real, and having to manually reconcile all the btc address and internal records. a
permanent solution is the ONLY real solution. putting a short term solution to this issue is far worse than halting withdrawls and figuring everything out correctly.
pushing transactions out makes a lot more sense with "personal" wallets, not for exchanges that use shared wallets and have complicated internal networks.