write.as does support custom CSS and JS, so you can, in theory, make look however you want. It isn't quite as light as Bear is, but it's no Medium either.
oh interesting! Yeah I actually hadn't been to their landing page in a long time, totally agree with your there (and feel like it doesn't do their actual blog product justice - to my tastes at least their blogs are perfect, low-key but elegant and very readable).
It looks simple, but isn't technically minimalistic with 77KB .css and loaded fonts. The first page load was actually visibly slow with the fonts repainting in a different typeface.
Everything fits on one screen, the font size is much more bearable, there's no unnecessary columnization or links to other parts of the site.