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.
Excellent solution.
Now when BTC-E and Bitstamp has similar problems, the bug that MtGox highlighted seems to have credit. Might Gox who cause similar issue with at their competitors exchanges

So now the ball is back at the bitcoin faundation. Bitcoin still in beta, might sadly not be so smooth yet.
It wasn't the issue with Bitcoin, but how they handled the situation by spreading FUD and passing the blame for their shitty service.

that is exactly the picture i was expecting here, as i clicked on that topic!

Ditto.