I really agree with your idea of the size of a community needing to have rigid laws to bind the society. At smaller scales you can probably get away without much, but we don't have those sorts of societies anymore!

I was taken by your idea of community service as "punishment", the more I think about it, the more sense it makes than having a monetary fine. Although, that said, I would also argue that time is not an equal resource either... a single parent that is racing around with kids, would have much less spare time (that might need to be bought with babysitting/creche) than a person in a secure job with paid leave.