Yeah, that's the other thing with this flippening idea. It can be seen as an attack vector. If ETH flips BTC, then we'll always be wondering what's going to be flipping ETH, instead of trying to improve the best thing we've already got. Altcoins can be a great way to criticize Bitcoin, which is important for progress--but if they surpass Bitcoin, then they have already foreseen their own death--they must also be flippened.