In line with the proposal of Shog to improve the reject reasons, I think we should also teach reviewers to search for plagiarization whenever they hit a tag wiki/excerpt edit. So, I suggest that audits geared towards this end are also imparted to +5k rep reviewers that use the Suggested Edits queue.
The objective is to make reviewers aware that dumping articles from Wikipedia et al is unuseful and potentially harmful for the site, and transmit the same sentiment to editors.
npm install gulp
?