Why is unrestrained, perpetual mobility permitted in this game?

For the life of me, I can't figure out why the people on the Champion Design team think the champions Kalistaa and Yasuo are healthy for this game. We've already established many times in the past that champions with unrestrained, hyper mobilty that can ALSO do just as much damage and be just as effective as other champions in their categories, are extraordinarily toxic.

Kassadin, Nidalee, Zed, Leblanc, Lee Sin, Yasuo, Lucian (after "nerfs" lol)

These champions were/are already extremely frustrating to play against. Sure they're fun for the person playing them because you're so insanely powerful. But for the rest of us, it sucks. Some of us might even want to play skillshot champions. But against a champion like Kalistaa, gl consistently hitting any type of skillshot. In fact, playing against Kalistaa's recently makes me just want to rage quit in a way I've rarely felt.

And I know, "Noob, just play champs without skillshots and that have hard, targeted CC." Well, maybe I think it should be viable to play champions with skill shots and still have a fun, occasionally successful experience. So thanks Riot for the new FotM cancer, and keep making such well balanced champions like Kalistaa, who renders 90% of the skillshot champs in the game ineffective. I can tell ALOT of hard work went into making a champion with literally unlimited mobility. Why not give every champion the ability to hop around twice per second, then maybe it'd be fair competition.

So much for accurately and appropriately valuing mobilty power contribution.....