My only problem is that when pasting SVG directly from Illustrator it finds an invalid character at the end and refuses to use it. I have to paste the SVG into an editor, remove some invisible character at the end, and then paste to svgomg.
I reported this and offered to PR but never got an answer: https://github.com/jakearchibald/svgomg/issues/145
1. Just fork it and use your own version until the PR is accepted
2. Directly email the maintainer if you think your PR is worthwhile
3. If you have a bunch of PR's that are pretty useful to others, consider making it a real distributable (and not just a personal) fork if the maintainer still doesn't respond