So my biggest concern with killing the 2 diff thing are the silly mapsets this now allows.
The point of this change was so that we'll be able to have more 4 minute Insane+ maps ranked. But removing the 2 diff thing now allows us to have a 3:30 single Hard set or even a 0:30 single Easy set, which let's be honest isn't contributing to the ranked section in any meaningful way (in most cases) and seems counter-productive with what the changes are trying to improve.
Consider also that a typical TV size spread is maybe 6 minutes of drain. This change now allows us to have 4 minute long songs with maybe 8 minutes of drain. That's reasonable enough. But now it also allows sets with 3:30 minutes of drain, or even less (I realise you could've already made EN spreads in the past, but I'll get to that in a sec).
This change was put in place so that newbie players stuck to their shorter songs since those are typically easier, and experienced players had more access to longer songs. So why are we allowing sets with only low level difficulties?
I wouldn't put it past people to try and rank a song with only a Normal diff or something along those lines.
It's even been done in the past for 5m+ songs. This would be favourable for beginner mappers, especially those who's only goal is to get something,
anything, into the ranked section. Instead of learning to build a full spread, those mappers will just try to push their single difficulty Normal into ranked.
I understand that some songs wouldn't benefit from forcing harder difficulties into the set where a single Normal would probably suffice (see: R3 Music box), but it's not reasonable to relax the rules to the point where we could get upbeat anime openings with only a single Normal on them.
Therefore I propose this guideline:
Guideline wrote:
The highest difficulty of a mapset should correspond to the general feel of the song. An upbeat anime opening should have an Insane or Expert for the highest difficulty, while a calm piano piece can have a Normal as the highest. This is to ensure that the most popular difficulty of a mapset will properly represent what the song offers.
It's a guideline since we can't really draw solid lines on what is upbeat and what isn't. The wording is open for discussion too since I don't know the music theory word for the 'feel' of a song (I was thinking 'timbre', but I think that's for individual sounds and not a song).
I think this is a reasonable compromise to killing the 2 diff rule, since it'll stop people pushing single Normal sets when the song can clearly support an Insane, while not forcing the people who do make higher difficulties for long songs to add low effort difficulties.