I've been using the command-line Roma a bit, and find there are some simple improvements we could do to documentation:
1. "man roma" gives s simple manual page which states clearly that it doesn't provide complete documentation. However, one useful addition would be to add that "roma --help" will give you better documentation. This would require a minor change to roma.1, if I understand correctly.
2. "roma --help" is much better, but this bit:
--localsource= # local copy of P5 sources
is not helpful. I had to hack around quite a lot before I discovered what would actually work; in my case, I had to point it at the guidelines-en.xml file in the P5/Source directory. I think fixing this would require establishing exactly which file it's best to point at for this (other suggestions have included the elusive p5subset.xml), and updating the documentation in rom2.sh (if that's the right file).
If I'm right about the changes needed, and where to change them, I'm happy to make them, but Sebastian should make sure I'm on the right track first.