To be entirely fair, there is missing money in at least one escrow transaction in which minerjones was a part of.
I don't think it would make much sense to start out with one of the keyholders who has a history I describe.
Considering that minerjones is statistically the most trusted member of the forum, who has escrowed large amounts of BTC for the forum, I'd say that he is a pretty good pick. Regardless of that though, anyone could have been picked in minerjones' place and it wouldn't have made a difference provided that the other keyholders are trusted enough to not conspire with them to steal the coins.
I'm absolutely sure that theymos did his due diligence before picking the keyholders considering the massive amount of money at stake.