I agree that ETH is looking like the next king. For 2018 at least.
I have been concerned about Tether for a while now but at the end of the day it's got a smaller market cap than BitConnect did when it went under so no doubt if it goes down it will dent the market, but hopefully not too badly.
I'm still trying to wrap my head around why it would be bad for BTC take your money out of tether and put it into BTC and bam it goes up rightttt?
Yes, its a bit of a unique one. With Tether it is kind of a fiat gateway itself, but if the fiat redemption is dead and there's a rush for the exits - then the only exit is to rush back into cryptos, thus pushing them up.
I think the overall loss of confidence and damage to broader crypto sentiment is the concern.