I don't think there will be a supercoin at least for some time. It'll be like the breaking up of USSR. There will be a bunch of dominant coins. Dash and ETH are the most likely to be standard but it could even be USDT. There have been too much greatness burried under the shadow of BTC and it's all going to pop up. Different exchanges will even adopt different coins. I mean this is still a free market. Nobody will dictate the standards.