Another metric i'd like to see introduced (pure wishlist here, i'm sure it would be harder to do) is to give more weight \ trust to reviews given by people who have given more reviews, or been on more rides within the database - since their rating is likely taking into account a far wider comparison...
In other words - Dodgy Dave signs up, logs in, and gives a 10/10 rating to the travelling Crazy Mouse - because he just so happens to work there. He logs off, never to be seen again.
Meanwhile - Gazza comes along, and enters a review for a new ride in the database (that he created only a few moments ago) - this brings his total ride count to stupid-hundred-and-one.
Gazza's rating should be trusted a lot more than Dodgy Dave's... this of course does mean that if Dodgy Dave comes back, and starts reviewing more and more rides, that his overall rating on each ride would gain more confidence as he completed each review (makes a negative skew a lot harder to achieve without a lot of work)
Unrelated, but something else i'd like to see is an 'I agree' button. For many of us, we feel the same way about some rides (and grossly differ on others). If we disagree with a review, i'm sure we'll make the effort to express a differing opinion (thats usually what the forums do) - but if we agree with the review - then a simple 'i agree' would give that same rating more 'confidence' in the system - effectively it would be another rating of the same value - and would be the database equivalent of an up-vote. Users would have the opportunity to change their 'agreement' the same way they can change their review (except changing agreement would require a full review entry), but you would only be allowed to hit 'I agree' once - so you couldn't go in repeatedly and upvote multiple times.
I have no knowledge or idea on how hard these might be - but wanted to raise the ideas for consideration should it be possible.