I think this has been suggested before, but I gave up searching for this after I hit the 90th page in the search.
I enjoy playing maps with extreme SV like https://osu.ppy.sh/s/153038, and I don't see many maps of these kind. So why not have a mod that does it for you? The SV mod would make random SV changes as you play such that it would go from 0.8x to 1.4x to another value randomly. I suggest there being limits to how high and how low the values can be to avoid it being too slow or too fast. Also The SV changes would have a smooth transition and not sudden.
While I linked a mania map, this is applicable to all other gamemodes as well. Well then only mania it is! I think it's a nice way to learn playing by hearing the notes instead going by visual cues. I can't imagine how this may affect the difficulty of a map, so I would just leave the choice to make it a ranked or unranked mod to you.
I enjoy playing maps with extreme SV like https://osu.ppy.sh/s/153038, and I don't see many maps of these kind. So why not have a mod that does it for you? The SV mod would make random SV changes as you play such that it would go from 0.8x to 1.4x to another value randomly. I suggest there being limits to how high and how low the values can be to avoid it being too slow or too fast. Also The SV changes would have a smooth transition and not sudden.