There might very well be a problem, and no matter how we end up solving it, we should have some solution ready.
It isn't a problem, it will never be a problem. The entire global economy could function on 1 BTC.
Confiscating property is theft. You don't own anything on Blizzard's servers. Those conditions are made perfectly clear. Anything you do on their servers remains their property. If you don't agree then you can choose to not use Blizzard's products.
Not if the currency is designed to work that way. It depends on how set in stone you think the Bitcoin rules are at this point. The answer, I'd imagine, is "very"
But it wasn't designed to work that way. Bitcoin was designed to be IRREVERSIBLE. This isn't a minor protocol technicality it is a cornerstone of the entire social contract between participants. Bitcoin tx can never be reversed.
To later change the rules and such a fundamental rule was irreversibility is immoral. Taking the property of another is theft. Now it may (and likely) isn't a crime but that would only be due to lack of legal precedent on Bitcoins. We should be arguing for further reinforcement (Socially, politically, legally) that Bitcoins are property and subject to the same legal protections are other property.
If Bitcoins aren't property then Mt.Gox (or any other entity) has a right to simply take all the funds deposited with them without legal or financial consequence. Is that the road you want to go down to "solve" a problem which has never and will never exist?