FYI, I tweaked the body text size in the grey theme (and made it vary slightly according to display pixel density). Take a look—it might be a bit better for you now.
You've also changed the font, right? Somehow I can't even reproduce the old bad look by changing to Fira :-) Anyway the new look is great, thank you! My only remaining nit is that
Might as well go with a bang.