I haven't published anything in ages here, but not for that reason. I've always enjoyed drafting stories in actual text editing apps, such as Ulysses or, my favorite, iA Writer. They also have Medium integrations that allow you to publish directly to Medium from there. I know many other similar apps also have this capability.

It makes sense to me, from Medium's perspective, to optimize the app for readers. In a vacuum, they would next release a second app, optimized for writers (same as YouTube has a second app, YouTube Studio, with the features only video creators care about). However, in the real world, there's basically no need for that, since there are already those other apps that are already optimized for writing and drafting stories.