If the orig dev tells the exchanges he is active and wants his coin they will never switch to this new blockchain.
that is a possibility but i think its unlikely, in the rare chance that it does happen we will still go ahead with a new coin which people can exchange thier globe for. with a burn address provided before hand for those who do wish to switch to a new coin. As ive said before do people really want to be holding a coin where developer disappears for two weeks without a word?
Either way it looks like a pretty decent plan. The coin (new or old) will most likely be better off.