It all really depends on whether or not the funds were siphoned out of Mt.Gox, or if they are still there in a (currently) inaccessible cold-storage wallet. If

It all really depends on whether or not the funds were siphoned out of Mt.Gox, or if they are still there in a (currently) inaccessible cold-storage wallet. If they were siphoned out -- especially over a long timeline -- I agree with you completely. The cascade effect of a rollback would be fatal (not to mention the precedent set would be...interesting, even if the Bitcoin ecosystem survived). On the other hand, if the coins never were spent, and are just sitting there because the private keys have been lost, it's more straight-forward to fix for the protocol. It certainly won't be easy, and would require a major rethinking on how to attack the problem. Also, while people affected who have coins tied up in a "lost" wallet are interested in having those coins released, I'm sure that there are more than a few people who want the opposite. Having a known condition where ~6% of the existing coins have been removed, most likely permanently, from the monetary supply means that their proportion of current holdings would go up (and, in turn, would see a corresponding rise in market value).