I feel like it all started around the time of Jarv and especially Lee. It was then that it seemed like all new champions were getting dashes, or what we called them then "gap closers." Whenever it took off doesn't matter much now, what matter is that mobility has swept the field in it's influence and is getting out of control.

Mobility is, in all PvP games, the single most powerful stat.

What do! D:

From what i've seen, there's not much you can do except make everyone reasonably mobile, or give those who aren't very mobile ways to stop the mobility of those who are.

Going with Riots logic on supports, they should nerf current OP mobility moves and avoid buffing/adding others.

But that logic only applies to power creeps, it seems. Mobility creep? ENFORCE IT FUK YEAH!

Create Anti-Dash/Flash items or summoner spells.

The idea that comes to my mind is a 4 second Wide Area field Flash/Dash lockout. A limited version of silence that shuts down self-repositioning abilities (not +movespeed).

Give people tools to prevent easy disengagement.

Rather then nerfing new champions mobility, blame it on the old champions!

give all champs a dash boom fixed

Make those without dashes hit hard as hell to compensate (Like darius!)