I had idea like that, I will post my suggestions/criteria how it could work later. Maybe
First of all - maps with scoreboards that don't give any pp should overtake the "approved" name, currently approved maps existing make no sense, it's just a ranked map with long enough difficulty (inb4 total score bullshit no one cares about)
Biggest problem is that it needs some sort of approval team anyway. BNs have a lot of work, so either they would approve maps like that in extra time or it would require making completely new team, up to osu! staff if they want to create something like it.
Approval criteria:
-Proper timing (crucial)
-At least basic hitsounding
-One diff only, preferably with some sort of minimal star rating (4-4,5 should work for osu!)
-At least 1:50 of draining time
-Map shows "intelligent design" - it shouldn't be just few minutes of retarded square jumps, it should represent the music somehow, just without being bothered about stuff like kiai time, proper slider velocity etc
-No extreme overmapping
- +6sp minimum? Just to guarantee some sort of insight from modders or that mapper actively takes a part in a modding process on other maps/sets
Biggest problem here is that this sort of approval could easily get out of control and create a circlejerk on larger scale, where friends approve eachother's gridsnapped copypaste. I still love this idea, it would let some mappers get more recognition and players show off their skills on something more crazy then we are used to.
Also I think it would be a good idea to seperate these maps from officially ranked maps, so stupid people don't start blaming osu! staff for promoting "cancer". I would be ok with a situation where they don't even appear in "Beatmaps" section, just let them have seperate forum. This way better maps like this would be played more and spread across the community through multiplayer, pms and spectating players, resulting in some sort of natural selection in terms of popularity