We have already discussed this point on Gox Self-help some time ago. It has been shown that probably a majority favor the "last balance" solution. This also fits well with your assessment. We had agreed so far:
"The remaining assets in Bitcoins should be distributed to creditors
proportionately to their final Bitcoin balance (as seen on mtgox.com).
The remaining assets in legal currency (FIAT) should be distributed to
creditors proportionately to their final currency balance (as seen on
mtgox.com)."
https://wiki.olivere.de/goxwiki/ClaimsGoxSelfHelp(Auth needed)
There are a lot pro and cons but overall - I think - every other solution would be much more complicated and would be perceived as unfair by the most people. That will not fly by. People want the 200,000 coins divided fair. People want there money and Bitcoin is money.
The problem is that the client's opinion may not be relevant, if there are laws/precedents that determine how claims are assessed. If the law says to use method X, and
one client tells Kobayashi that he prefers method X, it will almost certainly be method X. Even if all clients say that they prefer method Y, Kobayashy may say, "sorry, I must follow the law and use method X; thereafter you get together and re-distribute the spoils among yurselves as you like".
That question should be posed to Japanese bankruptcy lawyers and/or to Mt. Kobayashi. Didn't any clients retain Japanese lawyers to advise/represent them at the meeting?