let me start off by saying I am new to speed running in general, and am not very skilled at EU4, so I am not sure how this idea sounds. I believe forming Bavaria should be a category. My reasoning for it is that forming Bavaria doesn't provide a large challenge, unlike other categories, which would make it easier for new people to the game to speed run. As another reason, it would be a quick speed run, which there aren't many in Europe excluding the any %, like Nepal. I completely understand if it's a bad idea, but I thought I may as well suggest it.

I don't personally see any particular problem with a Bavaria run as such, and it could be nice to have more nation formations centered on Europe since that's the region most players are most familiar with, but personally I would prefer a slightly longer category tbh. While nation formations such as Mughal Empire and Japan might be a bit more difficult, they're still rather short, and the only semi long one we have at the moment (besides Roman Empire) is Golden Horde (but even that one could be pretty short if optimized enough).

But I'm not necessarily opposed to the idea of Bavaria either. I'd recommend you join the Discord server and post your suggestion there, since that's where most of the community activity and discussion takes place.