Hi Christof,
I think what you describe with PIDs is best handled by saving params to file(s) and restoring as needed. Though of course that requires some foresight and planning
I do agree it would be nice to reset certain sets of params to defaults while leaving others as-is. Unfortunately the defaults change between fw versions, and perhaps even custom builds. Trying to keep track of all that would be quite a chore. The best place to get the current defaults are from the FC, but right now there's no way to get those w/out doing a reset of all params (setting config_version to zero).
I liked Marcus' idea because the question of how to do a "factory reset" has come up a lot in the past and one currently has to dig in the docs to figure it out (I think it's in there somewhere
). But I see your point, it's not a commonly useful scenario.
Best,
-Max