A question about mobility

We know that ungated, general mobility is powerful.

That is to say mobility that does not come at a cost greater than a cooldown and which can be used in any situation.

This is most noticeable in assassins. While they need mobility to make flashy plays (which, I am sorry to tell you, are actually very good in moderation) it sometimes makes them too safe. They can just hop over a wall to avoid a gank, or perhaps just run away when the going gets too tough.

So there are a few solutions. One is to heavily gate mobility through resources - Hi Kassadin! While necessary in Kassadin's case (the horror) this method offers little interesting gameplay (although the mana restore on his W is a neat way around this - well done designers) and, perhaps more importantly, is annoying. You feel held back, constrained by a pathetic, now mostly transparent bar.

An other solution is to make mobility strategic. Rek'sai actually rivals Kassadin in mobility IF she has a network of tunnels built up. She has to prepare her mobility. This, to me, feels like a much better way of controlling mobility.

Other solutions include fixed distance dashes (which don't really go noticed in most circumstances however much weaker they are) and enemy targeted abilities. Of course, in cases that lack situational counterplay, this strategy doesn't work. Take Yasuo. If you are forced to fight near a minion wave then that is it. His mobility is near insurmountable. Away from a minion wave? Easy! Yasuo lacks what Rek'sai has. A real way for the opponent to counter, or limit his mobility.

So how else can you control mobility, particularly in combat? There are a limited number of ways of controlling mobility like Rek'sai's, and some good ideas, like Yasuo, turn out not to work in practice. Gnar's mobility - the double hop - is also an experiment that I believe failed. While it is short, his jump is long enough in most circumstances that the extra hop is just a little extra - something that is nice to have, not something that would really be missed.

The only way that I can think of is based entirely in the opponents positioning or play. While the number of Rek'sai-esque possibilities is limited, there must be a few more if we think hard enough. Furthermore, there are many things we could do with mobility of a similar vein to Quinn's - bouncing off your opponent, the enemy acting as a mirror, reflecting your position, a pinball-style jump, perhaps.

So I have two questions. First, Community, let's help Riot with this. A few thousand heads are better than one. We all play league, we all can help. What new, gated, forms of mobility can we think of that keep the game fun and allow for flash that doesn't come at the expense of older champions.

Secondly, Rioters, if you have the time and the inclination, what have you tried (that hasn't made it to the live servers) to make new mobility healthier? I would love to know all the little details you can give me.

Many thanks for reading this. I hope to have some interesting discussion with all of you.