Writing a good review is much tougher than anyone who hasn't tried it thinks it is. Among the issues to consider is figuring out how much commentary the audience wants or needs (the panning was right to left instead of left to right...does that matter, would anyone but an anal retentive geek notice...or care... or want it pointed out?), how much credibility you bring when you issue opinions ("x gives a terrible/great performance, he/she is wonderful/just awful). One reviewer critiqued my narrating style by saying I was "copying CNN" in the style that they use to pretend they are non-biased..WTF? I mean, I might sound that way but I read news for 20 years...it's pretty safe to say I wasn't copying anybody. Now of course, if that wasn't the right approach, fine...but what kind of value does that kind of comment add?
Bottom line, reviews are important tools for helping to raise interest in fan productions and helping to lay the groundwork for improved quality.
It might also be well to remember that while the fan productions in all media are by nature, mostly amateur with production teams and talent who vary wildly in experience, background and sheer talent, the same might be true of reviewers and anyone making a plea for some amount of slack on one end should be prepared to grant that request in the other direction.