The best solution for games that ran better under the 3.5 HLE audio is to...use that version.
But I would like to impress upon you that if users are intentionally using outdated versions of software because they actually function (for them) better than the newer version, that is a sign that maybe there's a problem with the latest iteration. More features doesn't necessarily mean better; and in this case if more accurate DSP emulation actually means lower quality audio, that is a use-case scenario where the less-accurate but fully-functional HLE was actually better.
Though certain games that require annoying things like safe texture cache accuracy (or worse, EFB copies to RAM) are problematic when it comes to synced audio; these things are slow, and the game likely will run a bit slower at certain points...leading to irritatingly choppy audio.
It seems to me that introducing an option into the menu allowing users to choose between older and newer HLE implementations, /or/ the audio syncing functionality of it (if such a thing is possible...), would provide a desirable option for every user (except the games that never worked).
But I would like to impress upon you that if users are intentionally using outdated versions of software because they actually function (for them) better than the newer version, that is a sign that maybe there's a problem with the latest iteration. More features doesn't necessarily mean better; and in this case if more accurate DSP emulation actually means lower quality audio, that is a use-case scenario where the less-accurate but fully-functional HLE was actually better.
Though certain games that require annoying things like safe texture cache accuracy (or worse, EFB copies to RAM) are problematic when it comes to synced audio; these things are slow, and the game likely will run a bit slower at certain points...leading to irritatingly choppy audio.
It seems to me that introducing an option into the menu allowing users to choose between older and newer HLE implementations, /or/ the audio syncing functionality of it (if such a thing is possible...), would provide a desirable option for every user (except the games that never worked).