Terrain obstructions can be exploited for double attack speed on projectile (bow) skills.

So I came across a funny little 'feature.' So far it works for every projectile skill I've fired out of my bow, including sky-bound shots like vine arrow.

Target next to you and fire repeatedly as fast as you can. Observe your maximum attack speed. In this way, there is no difference between holding the button and hitting it as fast as you can manually.

Target any spot on the opposite side of a wall or obstruction that causes your shot to land before reaching the cursor's target location. Holding the button will produce the same attack speed as before, but pressing it as fast as you can will get you about a 100% increase in speed you fire at. One caveat; it must be a target inside the map, not one outside the outer edge of the actual drawn map.

The end result of this is actually engaging gameplay, because I'm always trying to keep my enemies between me and an obstruction I can click the other side of.

But I'm guessing I found something that was put in to try to take off some of the sting when you click to target a skill and get told "nope, sorry, can't do that, here, get through the animation faster so you can actually hit a target you want to hit."