Although KF's "feel" is still lacking, I respectfully disagree otherwise.
While the highly visible rationales for Sloan not to play Fes included KF's off-court antics and his offense (especially relative to a moneyball rainmaker from Turkey), Fesenko was still a factor off the bench multiple times, including a respectable performance in the playoffs vs. the Fakers. And of course if Fes had had a Millsapian (a.k.a. paperboyesque) work ethic, then he'd probably be working on the second or third year of a substantial multi-year contract by now. But to say that "we" gave him plenty of opportunities understates the importance of
any player--especially a big--to get a minimum quantity of minutes on a regular basis in order to develop. Fes--whether he "deserved" so little time or not--logged a mere 1089 regular-season minutes over four years; that's less than Ostertag (also a player who had been accused of poor work ethic, weak offense, bad free-throw shooting, and even making Sloan go "sideways") logged in two years.
https://www.nba.com/playerfile/greg_ostertag/
Given that the 1995 Jazz didn't have a tempting alternative at the 5 spot (not one that I can recall) like the 2007 Jazz did (Slowkur), Sloan had little choice but to play Ostertag (also in part because he was a first-rounder, which coaches tend to give more of a chance than minimum-level second-rounders, unless the latter is a Paperboy-like producer). But the reality remains: few players, if any--from superstars to scrubs--are unlikely to develop if they don't get minimal minutes for a reasonable period of time.
My definition of "minimal" is at least 8 to 10 MPG; my definition of "reasonable period" is at least a year or two on a regular basis. Fesenko got neither (a thousand minutes over approximately a theoretical 70 available games per year is <4 MPG), even in the occasions when he contributed, and unfortunately he didn't transform such contradictory incentives into more motivation. A few bouts with injuries and illness didn't help.
Kanter is probably better now, and he probably has a higher and more visible ceiling (as does Favors, of course), so unless the Jazz really want a 5th big to replace Okur, any discussion of Fes back to the Jazz is moot, and it's not like Corbin gave him any more opportunity than Sloan did; Favors was already favored for development time. But part of me wants him to have another chance at the NBA just to show Sloan (and Fes bashers) what development time can do. Same goes for Koufos, who has also barely sniffed a total of thousand regular-season minutes over three years (and is doing decently in preseason play on a depleted Denver team).
https://www.nba.com/playerfile/kosta_koufos/career_stats.html
I'm optimistic that Corbin will figure out--by choice or by chance--the importance of court time for youngins; the financial tradeaway of Okur facilitates that process. Maybe, just maybe, he learned a bit about that principle between preseason game 1 and preseason game 2.