Crazy ideas: what about buffing Flash to close the mobility gap?
http://lol.esportspedia.com/w/images/7/74/Flash.png
For a while now, the conversation about Flash has been that it's overpowered, as evidenced by the fact that everyone always takes it. Riot's nerfed it several times over several years, but it's still rare to have a game that doesn't include 9 or 10 Flashes. In theory, if it were nerfed "enough", we'd see it lose ground to other spells. That doesn't seem to be anywhere close to happening.
I was thinking about the League of Mobility issues we currently have, with newer Champions having so many dashes and blinks that it leaves older Champions unable to compete. And it occurred to me: why not go the other direction with Flash? If Riot buffed Flash, it would effectively nerf mobile Champions and buff immobile Champions—if Flash is stronger, then Champions with lots of dash abilities aren't as massively ahead of those without dash abilities. There's a bigger power jump in going from zero flashes/blinks/dashes to one than in going from one to two; there are diminishing returns on these things.
I should probably clarify that last point, based on some comments. In the current situation, a Champion with a dash in their kit is way ahead of a Champion with no dashes. If we gave both of them an extra dash in the form of a buffed Flash, the gap between them would decrease considerably.
Perhaps this can be better illustrated with a reverse example. Let's say Flash were removed. One perhaps not immediately obvious effect of such a change would be to buff Champions with lots of mobility in their kits. Without Flash, abilities would be the only source of mobility.
Going the other direction, and exaggerating it for the sake of illustration, imagine that everyone had Flash on a 30-second cooldown. Mobile Champions would be much less powerful relative to other Champions; the ability to dash forward with your E is less impressive if everyone's got a Summoner Spell that does that.
I'm not at all convinced this is a good idea, but I feel like it's something worth discussing. On the one hand, it would make the problem worse in that (e.g.) poor Jarvan would never trap anyone. On the other hand, it would be an efficient way to buff less mobile Champions, and reduce the magnitude of the mobility gap.
