Hmm, good discussion.
Ideally, a good review thread should let folks cover what they think are the signifigant aspects of the title, good or bad. Anyone could post a review, but if there were a sticky at the beginning that explained what was expected of a review, I think that would be sufficient. If everyone had a clear cut idea of what was exected in a review thread, I think the rest would fall into place pretty easily. If not, the mods here do a pretty good job of policing the forums and keeping the trolls in check.
Basically the review is there to allow folks to find out more about a title and see if its something they might like. Several reviews over the same title pointing out different things would give most readers a much better idea what a title is about.
Even if it was something semi-formal like;
Title- self explanatory
Genre- action/romance/echhi/comedy/horror/mystery ect.......
Brief Description- what the basic storyline is about.
Similar titles- Is there a similar series?
Then follow it with the "opinion" portion
Stong Points- whats good about the title
Weak Points- whats bad about it
Summary- and this is the overall opinion of the anime by the reviewer.
I dont think it needs to be anything overly formal, but it should let folks say "I liked/disliked this title and here are the reasons why....".
As far as restricting things, I should have been more specific. IMO, the best use of a review thread would be for folks looking at titles and trying to get more info. No spoilers, no "naruto is better" responses, no commentary, just reviews. Thats not to say folks should not be able to respond, but they should respond in kind. So if you disagree with review A, they write review B, and demonstrate WHY you disagree by explaining it in the review.
Like I said, it doesnt need to be a big drawn out thing, but it would be nice to have something availible, so the next time a thread starts "Looking for...." you could say "look at these titles, and check the review threads for X, Y, and Z"