there is a roadmap for the evolution of btc in the future that can be found by searching it. Regardless of its evolution, btc has a set supply and eth will be allowed to inflate. I don't know what the catalyst of inflation in eth will be. As a dApp developer/user, eth is going to be an important crypto to hold - an important qualifier here is if you plan to use the eth ecosystem. If you're bullish eth, don't forget there are other dApp platform/smart contract coins on the rise: neo, cardano, eos to name the bigger players.

I saw a post on /r/cryptocurrency where the op said if your investing for growth to stay with the lower market cap coins. And there's talk of the flippening, that you mentioned. Best make your own pros and cons of each and weigh your own points against each other