I don't see anything significantly bad here, let them seperate away from us if they so wish, and they'll soon notice that it was likely the worst decision they ever made. It's top notch greed, but it will cost them dearly, that is almost a guarantee. But then again, I am sure that this is just the regular barking dog behavior - big talks at start, where later nothing happens at all
The bad part is that they are not going to separate for real
This is a poorly disguised, too obvious and easily seen through attempt to postpone the inevitable end of mining as we know it today (i.e. highly monopolized and heavily abused). The only possible explanation if Wu and Co are actually going to get done with Bitcoin is Jihan going totally nuts, which is unlikely. SegWit and further updates will surely eat away at his profit margins but they are pretty wide anyway to deliberately go for something as suicidal as creating a Wucoin. In fact, I wouldn't be surprised if Jihan denounced his actions later as intentional trolling (to save face)