Movement speed.....
I'm personally a heavy heavy user of movement speed.
However..... I'm getting kind of sick of Riot generally creating some "OP line" based on Ban/Win Rates, and trying to debate whether skill Q or skill W or skill E is the problem.
In reality...... nearly every single champion we generally are frustrated by...... ban.... and metapick has one thing in common:
Movement speed.
Not even Movement speed. Out of combat movement speed.
Stats actually back this argument up too:
Compare players who metapick 
to those who pick 
.
This is Duskblade's Pick/Win curves:
https://lolalytics.com/ranked/worldwide/platinum/plus/item/3147/
This is Youmuu's:
https://lolalytics.com/ranked/worldwide/platinum/plus/item/3142/
You'll notice on the aggregate, Youmuu's has far more champions over 55% compared to the whole who choose it than even Duskblade does. (In fact, the only champion taking Youmuu's who is below 51% is Sion.... and there are only 5 total champions below 53% with this item.
(The reason I'm making this comparison is "Lethality and Duskblade" myths)
Boots of Mobility
https://lolalytics.com/ranked/worldwide/platinum/plus/item/3117/
This is almost a meta pick on almost the entire champ roster.
Those who pick it more than 17.9% of the time..... all have more than 51% win rates, and it's also the third list of frequent move speed pickers who star champs with high ban rates, high win rates, and predominantly assassins, and the hooking supports.
Relentless Hunter
Harder to track, but in my experience, I can push 528 BASE move speed on a 
with it, and Champions who primary it as their third Domination rune are ALL high win rates.
Has anyone ever maybe considered.... the champs we consider OP.... just have gotten too fast? That just by buying a 900g item they can bypass the precise weaknesses in their kits? That maybe if Zed didn't reach one lane to rest in less than 30 seconds... he wouldn't snowball even when shut down by his counter laner? That he wouldn't need damage nerfs if he just didn't go 10/0 because of his runes/boots?
Movement speed dictates games more than any other factor. And they keep buffing it, while nerfing other factors.
