And so the centralization of bitcoin continues.
Every successful Bitcoin venture will increase "centralization" to a certain extent and there's nothing wrong with that. The great thing about Bitcoin is that centralization is not inherent - it's not structurally built into the system as with national banking systems and central banks, etc.
A free, decentralized market will necessarily coalesce around vendors of strength, as it should. To the extent those vendors start dissapointing customers, a dozen competitors are welcome to enter the market and try their hand.
Don't poo poo Mt. Gox's move here, I think it's both smart for them and a great relief to the btc community.