I think that, despite the problems that some of his designs have caused, in the long term it will be better for the game to have those champs. Why? Once there will be a moment where League has like 200 champs. And I can guarantee you that there will not be a single one who is too similar to Yasuo, Kalista or his other champs. Unlike some other champs, like Ziggs/Xerath/Lux who fill exactly the same spot and feel way too similar, all of CT's champs are vastly distinct from every other champ in the game.
Even Morde, who had a damn lot of trouble, has definitely changed the League landscape: for the past 5 years bot lane always had an ADC, which would always be a long ranged squishy who AAs you to death. Morde is the first champ ever that really changed that.
Yes, some of his champs may be overloaded, but as long as they can be balanced, I don't care. I know I am the only one in the world, but I (somewhat) like playing against Yasuo as a Ziggs. Every other matchup means I just press Q over and over again to waveclear and bully my opponent. Against Yas, I have to play differently. And despite the fact that I might get crushed, afterwards I still have a feeling that I just played an interactive, strategical game, instead of doing the same thing as always.