I think what we are seeing now is that Ethereum is a hedge for people with large Bitcoin positions. People are nervous about fiat in general (particularly in China), and can now hold multiple crypto positions with more confidence than they have in the past. This is pretty amazing for crypto in general as fiat hedging was really the only viable option available in the past.

Obviously the recent Ethereum run is all because of Bitcoin and the macro economic situation that is making people worry about their fiat holdings. I'd say that we are far beyond what the fundamentals would dictate for Ethereum, but I still think the downside is fairly limited due to the macro-economics that seem to dictate a global economic slowdown is coming along with a lot of worry about the Chinese currency and possible Brexit scenarios.