TwiiKuuMould (good) has been working on a KotH map and he attested that enforcing rotational symmetry does hinder creativity in significant ways
to sort of build on that, my opinion is basically that rotational symmetry on koth is really difficult because the playspace is lowered pretty significantly.
If you don't add the flank route to the end of the main route, as seen in bagel, you won't have one at all, given that you don't want a map with a 'main' reaching the point and then a flank route on each side. Ramjam is an example of a map where this happens, the result is that it's too big for 6s specifically, and that many flank routes is basically unwatchable (problem with my awful koth map)
The problem with that is that a flank fight where one sector has heals and the other doesn't, that's not really a flank fight and doesn't give you anything to work with as a flank player - each team will almost always roll out to the opposite side.
I found that it was almost impossible to create any flank without resorting to underneath flanks which, in my experience, are horrid to fight in and results in boring 'is someone watching it or not' play.
it's pretty much not even an argument that one side does get an advantage, I think the question should more be 'is it worth it' which in my opinion it is