These components are starting to show some age. Some basic simplification and spacing could help keep these feeling fresh. Mostly looking at removing timelineIcon and timelineIconColor as well as making comments singular items and place compound actions as individual items instead.
I feel like I am admitting a secret weakness, but when I use GitHub or another UI with a preview toggle I find myself missing the live updating preview that Phabricator has. I hope this admission does not invalidate my elite command line user neck beard.