I think he's a genius, he makes amazingly designed champions. What they need to do is take his ideas and SPLIT the champion concept in to two different things. Kalista? Could have been made into an amazing tank-support with her W and R being the focus of their kits, utilizing teamplay and whatnot. The other half of Kalistas kit could have been made into another spear throwing, rending champion focusing on the mobility passive, Q and E.
I just don't see why Riot lets him create full champions, all of her abilities have passives. There's absolutely no reason for that and that's what makes his champions too strong, they're just too overloaded. Look at Zed, why does his W give him bonus AD? Nobody knows... Yasuo? There's just too much to even list, the AS scaling on Q, W passive, Ult giving him his passive and all that free armor pen. Just flat out dumb.
Like I said, I love CertainlyTs ideas, all of the champions he has made are amazingly fun and unique. It's just that his ideas are too big, too much for one character. They really should start splitting his ideas into multiple champions, it's a win-win situation. They'll be easier to balance, less complaining from the playerbase and they have more champions to release!