I think an issue is that the systems implemented in the game have become more and more complex, and that this poses a lot of challenges on various levels:
While WT started out with quite moderate technological challenges, no sensors and avionics, simple ballistic weapons, we now have complex systems that need to be controlled, need to be designed in a level of depth that is a) as authentic as possible while b) be technically feasible and c) manageable by the average player, while those points a), b) and c) are quite contradictory.
This inevitably affects QoL for the players, and decisions have to be made that will for sure be happily embraced by one part of the player base, while being hated by another part of the community.
In Air, I myself am a Sim player exclusively, and sadly often observe issues where QoL suffers specifically for that game mode, that is better solved and not an issue in AB and RB.
A typical example for this are aircraft with ballistic computer but not able to use it in Sim because necessary information not implemented in 3D-cockpit. On AB and RB this info is displayed as GUI overlay available in HUD-only and external view, but the Sim pilot has no indicator how to aim his weapons.
The new patch adds even more of similar issues: Both the Anti Radar Missiles and the Active Point functionality have GUI overlay indications in AB and RB, but lack a similar display in the 3D-cockpit view only Sim game mode, and thus those functionalities can only be used in Sim with quite severe restrictions.
Another thing in general if we talk about QoL is how WT handles controls: Here I find it is handled quite inconsistently: some controls can well and easily be assigned to one’s controller of choice, or be activated/deactivated via options, or even both, but other functionalities are not handled the same way. Or they are available in some control mode and player view, but not in others (helicopters…). Or they are hardcoded and thus can not be used depending on control mode (MCLOS ATGM’s fixed to tank movement keys, so impossible to use if one uses manual transmission and axis controllers instead of keyboard/gamepad to control the tank…
And another one is just around the corner: As it looks now, all aircraft equipped with arrestor hook will automatically perform arrested landings on land airfields - a practice which irl is only performed in case of emergencies - which can not be opted out from by players who want to have a more realistic game experience - and all this for “QoL” to make turnaround time shorter for players, thus able to cut 5 seconds until they can take off again…