Again, though, nobody is arguing we should just go and sign some 6'7" lummocks who can't use his feet just because he's tall. People are just pointing out that, at 5'10", Timber would be notably small for a centre back playing in a pairing in the Premier League. I'm not saying it could never work but I think there are valid reasons to be concerned given the considerable pool of strikers in the league right now who can cause real problems in the air.
Further, City vs West Ham yesterday demonstrated that the concerns surrounding aerial ability in a centre back do not start and end with set pieces. City really struggled to deal with West Ham's out-ball because Antonio was able to win knockdowns and flick-ons quite consistently against Fernandinho.
I'm not even opposed to signing Timber but I find it quite facile to assume that aerial ability isn't going to be an issue for our centre backs because Ten Hag is going to have us playing "proper football".
Aerial ability will always be a factor and pointing that out is fine, but its importance relative to other aspects of defending is
massively exaggerated by some on here. It still makes up just a fraction of the overall game for defenders, even in the supposedly oh-so physical premier league. Meanwhile City are the
actual best defence in the league without being particularly tall or without their own weaknesses aerially, precisely because of the way they play.
And if our defence improves next season it is indeed likely to be because ETH gets us playing "proper" football that suffocates chances, because aside from that being how City function that's
also how his Ajax team with its two short centre-backs functions. You could also draw a comparison to the LVG era, which was statistically our strongest period defensively post-SAF despite involving another aerially suspect CB in Blind.
You mention Fernandinho versus West Ham but the prime issue there is that Fernandinho isn't a centre-back, not that he isn't aerially dominant enough. If that aerial ability dynamic was a massive issue for City in this league generally then they wouldn't be about to win the title having carried Dias and his 59.6% aerial duel win rate this season.