I don't think sumo will be consistent enough to warrant the separation but it's possible.

Would be nice to see!

Since most of the community is split between the different duel types, I think a centralized category where getting 10 wins could be cool. It would allow for a more skillful central category (as opposed to now, where getting a good time in your duel of choice necessitates running into a bot), and allow for different strategies in terms of which duel type to use since different categories have different speed floors and average speeds (for example, blitz and sumo can be some of the fastest categories at their best, but they can also be on average slower than other, more consistent formats).