So I just tried Ember Spirit in the test client. He's very fun, although I know I was playing him wrong. Figured I would max sleight of fist first as it was good for harassing and I went mid. I got a bottle but realized that he actually doesn't need that much mana so I wonder if that is even necessary. His stun thingy is pretty good for skirmishes but requires you to get close from what I saw and as you go back to your original position after sleight you can't just use that to go in. Ult could be very useful but you clearly have to be smart about it as it doesn't last very long. Probably set one up in your lane then go gank, then teleport back after gank is finished. And other uses I'm sure. I got phase and drums then stacjed battlefuries. Worked well.
I won't even try Earth Spirit yet haha, he seems hella trippy, going on my 'play when you get good' list. All the other changes are very welcome, and new Storm is awesome. Now bring on Custom game modes in the next big patch!