A new leaderboard where people are ranked based on how many #1 scores they have (an additional leaderboard, not replacing anything lol). Additionally, it would be cool if you could switch between #1's, #3's, #5's, #10's, etc
Eh. Not too keen on this idea. We can already see the #1 plays a person has on their profile page. Don't think a leaderboard is necessary or even beneficial at all
What Stefan said regarding #1. And WWW regarding most other stuff.
Anyway, such leaderboards can also be generated by doing the appropriate requests to the osu! API and evaluating the data. And oh wonder, people already had that idea, so enjoy it: http://top50.wa.vg/rank/