"Plagiarism can be a bit of a grey area though. Would you call DBZ Abridged plagiarism?"
See, this is why I'm so damn conflicted about all of this. So I'm going to pull a 180' and agree with what you're effectively saying here, and that is to maybe just leave ALL the stuff that has the potential to include grey areas out of flagging's purposes altogether.
Keep that blade's edge as sharp as possible...
That's a good way to put it.
A bit of scope focus gets much better rewards for the same amount of effort.