My /usr/lib/systemd takes 6.4 megabytes, so I think I could live with that overhead. Or I suppose just delete them manually.
What would actually be useful would be a generic OpenRC wrapper that would ingest those service files and provide traditional start/stop interface for them.
You mean the inverse of systemd.generator? Probably wouldn't be hard to make, but you'd have to be pretty committed to your init system to not just write the script by hand...