Hey since this is a "community" site why not get any of the people that can code in php etc. on here to give their names to you and then they can each write some code or give ideas towards it.
They do say that many hands make light work.
A few ideas of mine:
Organise the reviews by categories e.g. Games, Films, Books etc. that way categories can be added and deleted according to demand. Have a top five or top ten of the week for each category.
James' idea I think having a member system is a good way to stop rubbish being added. A spam and bad words filter may help too (simply store a list of words in a table in the database and search for thse words in a post).
The rating system is quite straightforward to do. Maybe having different icons for different categories e.g. a cd for music, joystick for games instead of boring stars.
The main problem to be considered is do you keep all the reviews? Or do you delete them/backup after say six months?
Anyway it does really sound that people really were interested in this but because of the current system they got bored. By having a membership system you have some sort of control over who posts. It would cut down the admin side of things considerably and I think may well help more people contribute more towards the site.
You may well think that I'm crazy suggesting the whole community programming thing. But I think if realistic goals are set and achieved then it would at least be an interesting social experiment. Also there are from what I've seen alot of talented people on these boards so why not make use of that talent?