If the member isn't citing Wikipedia as the source, then I don't see any difference at all between those two cases.  I've seen a lot of cases where people are copying stuff from all over the internet in order to answer questions and passing it off as their own original answer.  That's plagiarism.  The text spinning stuff is more devious, but we're talking about the difference between a criminal who leaves his fingerprints all over the doorknob vs. one that tries to clean up the crime scene--the offense is the same.

I don't think there's a problem with the way things are now, except that not all plagiarizers are created equal and there are two that I know of that I wish had gotten some leniency--but I also understand how important it is to be consistent with rule enforcement.

Hilariousandco, you know that when people get permabanned, they go right back to doing it with a new account.  Hell, you've even suggested it a few times and I've begged you not to give that kind of example to people.  So I don't think a signature restriction would work at all--they'll just abandon the account.  The merit solution has problems, too, unless it's a very high amount.  We know merit gets traded and sold. 

Part of me wants to see leniency for established members who may have fucked up early on.  Maybe there could be an amnesty date set somewhere in 2016 or something, i.e., if you plagiarized after x/x/16 but have a good post history/positive trust/[insert whatever else here], you'll be banned like everyone else.  It's definitely a tough call, because if you show mercy to some based on subjective standards, there's going to be an outcry from those who didn't get any mercy (and probably other members, too). 

I voted for keeping things as they are.