What would be the win in avoiding TrueType? Seems like we could easily convert any TTF files to PostScript Type 1 if there were an advantage to be gained.
This might be a misconception but I was under the impression that truetype fonts are a complexity and security minefield. In particular I noticed an st developer complaining (on the mailing list, probably) about the lack of a suckless font library when I concluded that it might be better to just do without them.
There is libdrw in suckless now, which still uses xft and fontconfig. Fontconfig and xft are ugly and require too much internal knowledge to be useful. The next logical layer in Linux evolved as pango and cairo. Both of course added HTML formatting and vector drawing. This is not needed to simply draw some text somewhere. And this is what a suckless font rendering library should do: Give it a font string and render at some position the given font without having to care about font specifics.