No need of a proper diff spread if a set of the same song has already been ranked.
Example:
https://osu.ppy.sh/s/40368 has already been ranked with a proper spread diff, therefore https://osu.ppy.sh/s/81010 could be ranked with no need of a proper diff spread. Even if the last mapset only consisted in several super-ultra-mega insanes, it should not need any low difficulty.
We have other extreme cases like https://osu.ppy.sh/p/beatmaplist?q=irony, https://osu.ppy.sh/p/beatmaplist?q=SWOR ... 0&g=0&la=0 and well popular songs overall. Plus it's not that uncommon for some player (also a mapper) to play some song on osu! and then feel like mapping it an working out a nice new difficulty for that song, yet they don't usually get ranked because that would mean they need a proper spread, which means normal, hard and maybe even a low tier insane if the original difficulty is extremely hard.
Example:
https://osu.ppy.sh/s/40368 has already been ranked with a proper spread diff, therefore https://osu.ppy.sh/s/81010 could be ranked with no need of a proper diff spread. Even if the last mapset only consisted in several super-ultra-mega insanes, it should not need any low difficulty.
We have other extreme cases like https://osu.ppy.sh/p/beatmaplist?q=irony, https://osu.ppy.sh/p/beatmaplist?q=SWOR ... 0&g=0&la=0 and well popular songs overall. Plus it's not that uncommon for some player (also a mapper) to play some song on osu! and then feel like mapping it an working out a nice new difficulty for that song, yet they don't usually get ranked because that would mean they need a proper spread, which means normal, hard and maybe even a low tier insane if the original difficulty is extremely hard.