A piece in Slate about the influence of Alan Sepinwall, generally considered the father of modern TV criticism, has triggered something of a discussion about the role of the television critic-as-fan. My AV Club comrade Myles McNutt posted a typically in-depth response, which brought up a point that I always think about when I engage with (or write) a review: the audience matters.
It's arguably the biggest issue with reviews. Anything that you write about, you have to pick a target audience. Usually, that target audience is you, or people like you, since obviously that's your position of expertise, but it's not always that way. The essential question, on a continuum, is: "The Audience Knows Nothing About The Subject -> The Audience Knows As Much As They Can About The Subject."
As with most continuums, the far reaches of either side can generally be ignored. Reviewing a video game for people who have never played a game in their life would be an exercise in frustration, and writing a review just for people who know everything possible about something, up to and including possibly making it, is too narrow to be useful. In general, the critic acts as a guide: they know about the subject in some rank between competent and expert, and they use that knowledge to help the reader learn more about the subject, or contextualize it better. A new Wong Kar-Wai film would likely get a review that explains how Wong uses image more than dialogue to create his films, and how they're generally light on plot while heavy on emotion.
Yet there is also a set of people, which includes me, who already know about that, and are interested more in how the new film would fit into Wong Kar-Wai's existing context. Describing his past style is mostly irrelevant to them. They want to know how it compares. At its narrowest point, the question then becomes "Is it better than In the Mood for Love?" If the critic's answer is "Yes," then they're telling everyone who already knows about Wong's film that this is fantastic and worth seeing immediately - but everyone else is out in the cold.
This push-pull with the audience happens across media. Games, based on sequels and existing engines, may have it hardest. Books less so, but nonfiction does often rely on a certain level of knowledge and interest in the subject.
Which brings us to television (and, to a lesser extent, comics). Games, books, and films can still be seen as discrete entities. Regardless about whether you've seen Chungking Express or not, you can still talk about In the Mood for Love. However, television, as a serialized story, is many discrete entities (episodes) coming together to make larger discrete entities (seasons) which in the end comprise the entirety of the show itself. So a critic can write about TV at any of those three levels, or even combinations thereof.
But that combines with the audience question to make it essentially impossible for television to be reviewed in a fashion that will be generally satisfying. Someone may be dropping in on the show for the first time. Someone else has been watching and talking about the show from the beginning. They're going to have wildly diverging expectations from anything written about the show.
Any critic who engages in an episode-by-episode writeup of a show is, by nature, going to appeal to the people who also engage with the show on an episode-by-episode basis. And generally speaking, that's good business - better to have the same few hundred folks click once per week than a thousand who click once per year on a season-long review. But that doesn't help the people who are interested in trying it out, or even those who have just started sampling.
My solution to this issue with games and other similar tends to be to have multiple reviews, with each reviewer's perspective made fairly clear. If a new Dynasty Warriors comes out, I don't need someone to tell me that they find the formula tired - I like the formula! Tell me how it differs in minute detail from other games in the series! However, even that doesn't work so well with television. Yes, if a season (or character, or storyline, or anything that can be separated out from individual episodes) deserves examination, it could be examined, perhaps by multiple people.
Still, the upshot of this is that critical examination of media, which is difficult in any other medium, is virtually impossible to do with television in a fashion that will satisfy the bulk of readership. All that critics can do, then, is all they can do.