I think that a paid membership is not exactly the way to go... Then (especially if the site changes hands, as did brickfilms.com several times) things could become unfair... Though, you do need money to keep a website up.
On the issue of this thread, however, I agree. There should be a new rating system. Maybe even one with a "letter" rating. (i.e. G, PG, PG-13, R) Though, it would have to be different, as to avoid a strong letter from the MPAA. ( lol )
I like the limit of a 5 star rating... 10 IS a little too much.
As for user ratings... Things would get too messy, I can already picture it. (Nothing against myself, but even I "manage" two accounts. Though, because the other is for my little brother, I only use it when he's around to actively participate) However, others would/could do this and "cheat" by giving their videos 5 stars...
However, a ratings board is a good idea. (Even if a new one) Maybe, as a test, you could put out a poll. And, those who passed it would be able to be members... Then instead of a "staff review" there could be specific reviews from "brickfilm critics" as I tried to do with my series (now on hiatus) CinematiCritics...
Either way, I do think something needs to be done... Even if it's to let everyone be a "critic," and find the average from all of the ratings (similar to how the current "stars" rating system works. Then there could be user reviews, ranging from the Roger Ebert's (heads of staff like Smeagol) to the generic paper reviewers (members).