Im not sure if we need this but ill pretend we do.
It all comes back to csgo for me. One of the last updates to csgo was adding a request players have been asking for all of csgo. "Scrimmage Mode"
In short its a non-competitive mode that you queue for like normal ranked play.
in long
https://youtu.be/3eTEFLUhF-Y?t=53
What I see related here is how Scrimmage allows players to try out new maps without the fear of deranking. People can try out new strategies on a more casual game mode. This could be added to Ni but rather than "deranking" its well a wipe.
Now for how maps are grouped Im, not sure however what I would do is put it on rotation so we dont get bored of doing the same 3 or whatever maps on rag. Every upgrade realise the rag maps go too hard than hard --> normal than normal --> rag. Maybe that too much work for Kip and others but you get the idea.
Like I said I'm not sure how you pick maps but what you could do is this.
Get the community to do a blind vote on maps that way a list can be formed of the favourite map to not so popular.
This way
group 1 for maps will be 1st 4th 7th ...
group 2 for maps will be 2nd 5th 8th ...
group 3 for maps will be 3rd 6th 9th ...
I would be against rag always having the "best" maps as nothing will change fast as new maps or old how do they qualify for such criteria?
Maybe a change like this will encourage map makes to focus on the less popular maps?