We're one injury (or run of suspensions) to Casemiro away from the Groundhog Day of the last few seasons. Not only does Caicedo cover that eventuality, he also slots into midfield alongside the Brazilian; he also affords the flexibility to approach different opponents with varying applications, be that pressing, sitting, stifling - it's a veritable mix of eclectic optioning and something we sorely lack as a collective with our single point failure before being reduced to McFred, yet again.
One might argue that a deep-lying playmaker and elite ball-carrier, such as FDJ is the optimal player, but they barely exist and ideally, we'd have both a Caciedo and a player of that ilk ably rotating in and out of the team ala Madrid or City.
Fact is, we have gaping holes in midfield and need two bodies there not one. Caicedo would kill multiple birds with one stone, and we need that profile of multifunctional player desperately.
The other issue is that Caicedo would preserve Casemiro's legs and potentially eke more time at the pinnacle for the Brazilian via us not overplaying and fatiguing him. No other player profile benefits Casemiro in that way (grafting and running for him/the team) even if the deep playmaker type assuages a different set of issues and has the ball do more of the work... think of these types together as a dual engine; over a full campaign they have the potential to be huge assets for one another both in terms of fielding at the same time as well as in rotation.