Nice idea but it needs a LOT of moderation to make it work (at least on a relatively small site like this dealing with a fairly narrow range of books).
It’s not so much that people deliberately abuse the book in interviews as that non-professional/inexperienced reviewers often write largely useless reviews unless there are people around to provide extensive guidance on the first few.
Anyway, I noticed a similar need, and have added this to the desired features for JGF. It would be a lot easier to add on to JGF since we already have an editors system (on the private prototype for the next version :)) and some volunteer editors already exist (having worked on JGF articles).
If anyone is particularly keen on reviewing a book they already have (dr anonymous?) then feel free to send a draft review to ceo @ grexengine.com and I’ll sort out an editor (or 3) to help you make sure it’s both informative and fair (both to the author and to the potential purchasers!) and we’ll put it up on the current JGF.