Some of the copy/paste spammers have already beaten this method in that they replace certain words, replace letters with symbols, among other things.
This fight in between good and bad will always be there. We are trying to do our best to beat them and I understand that it's not an easy job. By the way, good guide @OP.
I think it would be better to remove the incentives of the copy/paste spammers and/or provide incentives not to spam (this way).
At the end of the day, these spammers can use automation to make their copy/past posts, and can use technology to hide their activity, while the decision to ban someone is a manual process.