I agree, well said. I have come across a few pages myself, and I am not that active on Wiki pages either. Oh plus its fun to get your creative thinking flowing with writing up new and original content for a character! 

It's hard to find who exactly plagiarized a wiki page because it could have been one user or multiple people could plagiarize a single wiki page (though I seriously doubt it but nonetheless it is possible).

" Maybe there should be a way for a user who comes across a plagirized page to flag it as such so someone who knows the character well enough can come in and rewrite it later. "

I always check when I edit a page to see if it's been plagiarized or not. Still we need a way to find the user responsible for plagiarism on a page so they can be warned or banned.

Yup. A changelog would be incredibly useful.

Should we establish some sort of secret police on CV where we can inform on our friends and colleagues?   
 
In Soviet Russia, Comic Vine plagiarizes you!

you should take it up with the moderators. 

Or someone could just make a master thread of plagiarized content and it could be updated as people change it
-Virus