Don't you end up with PDF if you start with PS and restrict it to a subset? And maybe normalize the structure of the file a little. The structure is nice when you want to take the content and draw a bit more on the page. Or when subsetting/combining files.

I suspect PDF was fairly sane in the initial incarnation, and it's the extra garbage that they've added since then that is a source of pain.

I'm not a big fan of this additional change (nor any of the javascript/etc), but I would be fine with people leaving content streams uncompressed and running the whole file through brotli or something.

I thought PDFs can contain arbitrary PS.