No normal app (excluding control center and similiar stuff) should ever set a system-wide
default volume. You never know which hardware is attached. Take e.g. in ear speakers which
are usually way too loud on anything above 50% of stock computer audio jacks. Take e.g. a
user who has a very powerful sound system attached to his computer and uses system volume
to limit his sound system's power, …
With flat volumes, PA is just broken and pretty dangerous. And bad user experience.
I'd vote for "disable flat volumes ASAP".