Troff isn't that bad once you spend a bit of time familiarizing yourself with the syntax - and possibly buildings your own abstractions on top of the available

Troff isn't that bad once you spend a bit of time familiarizing yourself with the syntax - and possibly buildings your own abstractions on top of the available macro packages, -ms works but... SH? NH? .NaH. Or build a new one from scratch if you feel masochistic enough (not that I would know anything about it, nossiree). It's lightweight (I like to think the feather typesetting-Anubis uses weights a bit more), fast, produces a decent output, and it is simple enough you can use it to make shell scripts spit out pdfs.