Which is the sense of new rengar's w?

To use your emp ability in 1 rotation you have to jump from a brush and use all your abilities, ok, but which is the sense of an antiburst w, in an assassin's rotation???? I mean, if you use your w to try to burst a carry, how can you use your w against a burst? None can wait 3 sec( next q) to use an emp q leaving w in case of burst.....none except for.... The sense is that this new rengar isn't an assassin, it's a bruiser...... With this new Q ( animation it's too slow, pls speed up) doesn't feel rengar Anymore.

P.s with his old base stats and no more lifesteal proc (masteries) on q, his first clear sucks really hard. Pls fix