Chourio is already better than Frelick in the OF...
With reps, Chourio can absolutely be as good as Mitchell in CF. Who knows if he gets Perkins good as that's almost Prime Cain level, but remember Chourio won a GG in CF in the minors and played that position exclusively until this season grading as a future 60.
Honestly, Sal Frelick probably deserves to be in LF more often. And I doubt Yelich is suddenly going to stop playing in the field. Mitchell can play a good RF, and has the best arm of all the RF options.
Perkins is the only one who's really proven to be a superior option, but he hasn't shown that he can hit enough to be a surefire everyday player.
Bottom line is Chourio in CF is of greater value to the Brewers than Chourio in LF if he proves he can do it which every indication from his minor league career is that he can. He's got the contract that none of those other guys do to where he takes precedence.
I agree he's fine for now, but he did show he could handle the offensive and defensive workload in the minors. He won a minor league GG in CF in 2022 the same year he was MVP of the Carolina League. All the scouts have him as a 60 grade defender in CF.
I just think there's no reason not to work to transition him there when the value payoff in CF is so great. If he was injury prone that's one thing, but he's never spent a single day on the IL as a pro to this point. No need to "save the legs" of a 20 year old. Willie Mays, for instance, as great a hitter as he was, wouldn't have been Willie Mays in a corner OF spot.
Most interesting remaining question on Chourio imo is when does he take hold of the starting CF spot. Chourio has already mastered RF and is growing increasingly comfortable in LF (probably deserves a GG). Meanwhile, Mitchell, Perkins, and Frelick just aren't hitting enough to have the everyday CF spot on lock. Chourio clearly has all the tools to play at least an above average CF and his value would only increase were he to successfully make the transition.
My guess: He plays there a ton next ST, and he leads the Brewers in innings played at CF by the end of next season.