Now in 5e plus the current oned&d rules any type of flight also grants hover & perfect maneuverability
Which doesn't mean much unless you're comparing editions for some arbitrary reason, as though you're trying really hard to prove theres no problem with one thing (contrary to what most everyone else believes) by pulling any argument out of thin air that supports some other thing being a problem.
It is, in fact, okay to say that both these things are not well designed and that they, as a result exacerbate each other.
Its not an either/or.
And meanwhile, the assertion is false anyway. Flight got simplified, but hover is still an explicit ability with a changed definition.
If anything, the best fix is to enact a minimum movement for flyers each turn, and to make movement and speed identical rather than separate. This way, flyers have to underspend their rate to stay airborn, which will temper the usefulness of it.
Heck, the GM even needs to houserule that a player lacking hover can't use flight to ignore rough terrain & dangerous terrain (ie grease/caltrops/etc) unless the player actually uses some of their flight speed to not be standing on the ground
Thats not a houserule thats just how flight works if you don't have hover and haven't begun your turn in the air.
I see it more as the standard and what a large portion of players use, and certainly as an example for others, no matter how flawed you think it is
Which does not mean that adventure design as WOTC has presented is actually good, desirable, or anything the game needs to be revolving its rules around to make work properly.
Its like designing a buggy video game and then changing entire game mechanics around to avoid just fixing the bug.
You seem to have no qualms badmouthing just about every part of D&D (in various threads), but flyers somehow are apparently essential, that is a weird take and tells me more about you than D&D
Not everything in 5e is bad, and those other threads are most often covering its most egregious problems.
Flight isn't one of them, and at no point did I suggest or imply that they're "essential".
And again this cuts both ways, you defend something because for whatever reason you like it. All this is, is personal preference
I have no strong preferences towards flight at all. Your assumption that Im emotionally invested in flight being unchanged is unfounded. Not seeing a reason to overcorrect flight rules when your reason for doing so is to accomodate a far more broken and fundamental game design problem is not the same thing as loving flight rules as presented.
and published adventures need bigger adjustments when you have fliers.
If you buy an adventure and it cannot accomodate official content thats existed since 2015 then the problem isn't with the content.
We can extend the benefit of the doubt to adventures released prior to the Aarakocra itself, but since then, and especially since the race has been republished twice over, there is no excuse for official adventures to fall apart just because of one official race.
this never was my claim

throwing out fliers instead is a perfectly valid and simple alternative
Do keep in mind theres a couple different trains of thought going on here; this one in particular is in regards to DM created adventures, not officially published ones. So do not take this and try to argue that its an argument to disprove theres a problem with official adventures.
or maybe I design the adventures the way I want in the setting I want and flying is no part of that, and certainly not common at a minimum, because flying gets in the way of that.
Banning flying races is a valid option if you don't want to design encounters to accomodate them. (Disregarding that good encounter design would naturally accomodate them anyway, without any special effort)
does not mean that it needs to be am essential feature in every campaign.
Kind of strange to assume that just because flight exists its always going to be a factor and you have no choice. Like, you know ahead of time what your players are going to be playing as, and you always have the option to ban the races if thats your fancy, and if your players are agreeable to that then theres literally no problem.
And if your players are the anti-social types who will pitch a fit if you do this, and will otherwise go out of their way to abuse anything they can to make your life as a DM miserable, then all anyone can tell you is to find a new group.