Good points!

Personally I don't find it easy to recieve feedback, but it's somehow easier if I specifically ask for it. I certainly don't expect very many to join the effort, but those who join might enjoy some mutual benefit. Together we can achieve more than separately, and I think good writing will be a valuable asset in other contexts too.

I think I would personally just keep track of who I have helped and who has helped me. There will certainly be someone not paying, but after a few rounds no-one would count them in anymore.