On the review page, there is a one-sentence guideline on reviewing. I think that as the number of reviewers increase, it is going to become increasingly necessary to come to some kind of agreement about a standard way to handle the different 'cases' that arise.
I'm not sure if 'one question to rule them all' here is a good idea or not, but let's try.
Post an answer for each new 'type' of problem, with a suggested approach, then people can weigh in with comments and update the approach accordingly. Make the posts CW preferably.
(Obviously, don't bother posting links to problem posts, as they won't be around long - just copy/paste any relevant text)
EDIT IMPORTANT: There has been some (cough), 'confusion' about the semantics of 'flag for removal' in review. Some people took that to mean "this answer is ok, remove it from the reviewing list", whereas (as I understand it), it actually means "flag for removal from the site".
EDIT2 - (Shameless plug) If you find the answers to this question helpful, you may be interested in my Pro-forma comments script