I don't think reviewing games by committee is the right way to go about it. First of all you have to commit way more man hours to ensure said panel all play the game within the timeframe that you need the review (which is often only a couple of days). Also you're going to have a lot of cases where people on that panel disagree heavily. If one person thinks a game is a 6 and another thinks it's a 9, is it really that much fairer to average it to a 7.5? Also presumably this panel would be small, and there are a lot of people who review games at IGN so you're still going to run into the same problem pretty often since it's just a bigger group of different reviewers each time.

Plus another thing that people don't consider is that even if IGN's scale was consistent, you couldn't possibly compare it to other sites. Some sites still use scales where various components of a score (graphics, gameplay mechanics, etc) are averaged to give a game a score. Others, like Giant Bomb, are on a 5-point star scale. Others just do recommended/not recommended.

At the end of the line I think people just have to put less stock into the number. The number is there specifically because people freak out about it and that drives up clicks. And because aggregator sites like Metacritic exist.IGN is a business and whether or not they get hate for it those numbers probably make sense to keep around for their business.

And I don't think it's really misleading, because if you're basing game purchases on only numbers then you're doing it wrong anyway. People should find reviewers they like and follow them, they should read the actual words of multiple reviews if they're on the fence about something and make purchasing decisions that way, not based on some random number which isn't consistent within the same site, and certainly not over various sites.