It’s never ideal to be undersized as a CB because it’s a seemingly obvious weakness and inlet to attack, but the reality is the more important things for short CB’s is their understanding of their own bodies and limitations. Generally,*great* short CB’s are athletic marvels with tremendous compensatory leaps and immaculate timing and reading of the game and when and when not to contest bigger men aerially: Passarella; Cannavaro; Baresi; B.Wright; Ayala; Cordoba; Puyol; not one of them would people say were deficient aerially, in fact, to a man they were praised for their ‘surprising’ aerial prowess, but you don’t even have to look at those in that tier; players like Heinze, Mascherano; Bruce all of whom read the flight of crosses and the timings and in the moment snapshot superbly well, in fact Heinze and Bruce immediately go to the conversation of best aerial defenders United have ever had, such was their brilliance in any kind of aerial contest.
Point is, it’s not height that’s ruinous; it’s understanding and pre-emptive actions - you better be doubly good at reading play and positioning yourself if you’re short, is the point, so in and of itself, what needs to be asked about Timber as a CB is how good is he actually at being a defender? What are his defensive fundamentals like and does he use his immense physical attributes in unison with a good, core understanding of defensive actions? It’s not height that is the downfall; it’s being shit at defending, where a shorter CB has to be even more honed in the craft than taller ones.
Timber’s height wouldn’t determine anything in the PL; he’d just be exposed as a poor CB if constantly outdone in aerial duels.
Anyway, I still don’t know why the notion is he comes here just to be a CB when his eclectic nature really primes him for more adventurous roles, especially so with our gaping holes and need for players in multiple positions.
What can also happen is start the guy wide so he gets a feel for the league and the lay of the land, and then slowly integrate him to central positions. That can be after an outright RB comes in; it certainly doesn’t have to be: buy, throw in at the deep end.
But yeah, height is not a reason to avoid a CB unless he’s pint-sized, which Timber isn’t as he’s no shorter than Heinze or Puyol who were famed for their aggression and robustness over practically anyone active at the time they were playing.