Issue is that he makes far more progressive ball carrying runs than any central midfielder. As we've seen, this is good for counter attacking sides but not for sides that predominately see the ball. He's also not part of Nice's core players in the defensive transition, he ambles back whilst preparing for another counter attack. Although his ball winning attributes are pretty good, his defensive positioning isn't consistent, as he is always looking to get further forward. There is the argument if he can be coachable, but there is also the argument if his natural instincts get in the way for it to work, ala Kante.
This is a very good analysis on him. Essentially, Thuram would require a lot of coaching (without much guarantee of success) whereas Caicedo would slot in easier.