I once proposed an idea somewhere where you would have slots for how many extreme, insane, hard, normal, and easy diffs you can rank. The slots you have for higher diffs would depend on how many lower diffs you ranked and their length.no lmao.
This can solve the alienation problem CDFA is mentioning.
For example, if you rank 1 easy diff 5 min long, then that would open a slot for one of the hard, insane, extreme diffs.
If you rank 1 easy diff that is 1 min 30 sec long, then that would open a slot for hard and insane diff, and it would require another diff on same or different map to open a slot for extreme diff
I am not sure what the best combinations for slot unlocking be, so it would take some discussion to find what is best.
That's way too complex and unnecessary for something that can be solved in a MUCH easier way by saying "Map a full spread but the shorter diffs can be shorter than the harder diffs"