Understood. Perhaps you could make your improvements modular in some cases so that people can toggle them on, either as nginx modules, or compile flags in nginx core?
I think it'd be great if more companies released their own 'opinionated' versions that update with their infrastructure. Like if I wanted to host a OpenStreetMaps tiling server hypothetically using some features cloudflare has in their nginx builds. Makes it easy for white-hats to test, too.
IIRC I've been intersted in HPACK for small http responses where the headers are larger than the body, but if I wanted to use the HPACK patch I have to re-impliment it every time an update comes out that modifies the file.