Today I noticed myself doing the following:

1. Receiving an e-mail from DidHeLikeIt.com. Which, if you haven't seen it, is a very clever little website that simply shows you whether "he" (Ben Brantley of the New York Times, with an occasional sub-in by Isherwood) liked a show that opened.
2. Clicking on the link to visit the site to find out whether he liked Mr. and Mrs. Fitch.
3. Seeing this graphic:

4. Not bothering to read the article to find out the details of why Brantley didn't like it.

Have I over-marginalized the entire critics system?

Yes.

For the record, though, I usually make these snap judgments based on the contents of StageGrade (formerly Critic-O-Meter) which is a fantastic roundup of the sum of all the reviews averaged out to a letter grade.