When mode isn't a subcategory it's basically treated as an unimportant variable. Here different modes actually mean completely different categories so it should be a subcategory.
I also agree with this, and subcategory names should be typed without spaces (osu!, osu!taiko, osu!catch, osu!mania).
I have to agree with Awsumi, it would just end up looking very messy, you can click filter > mode > osu!standard and see all the standard plays if you wish. If you have a speedrun that's for example 3:33 on standard but 3:30 on multiple modes, the 3:30 will show up on the global leaderboards, and the 3:33 will show up on the filtered to standard leaderboards, so nothing overwrites :D
Greetings, dear osu! speedrunners! Today I'd like to tell you about an interesting idea we recently had, medals count speedrunning! The idea of this category is to get specific medals count as fast as you can! But you will ask me: *"Hey, but how is it possible? We can't use multi-accounts in
