That's not quite fair, Galaki.
Anyway, I think that a lot of the disagreement about Mario Kart's scores comes about because people think about reviews in two different ways. You can look at the game in isolation or as a sequel. If it didn't come from an established franchise, it might well have gotten 9s. However, we also expect improvement from title to title in a franchise, and it just doesn't provide that for most people.
If you're hardcore MK fan, you're upset about the increased accessibility and the removal of snaking. If you've played the past titles as party games, you don't understand why you can't play offline races without computer players and you really, really miss classic Block Fort. This is an important point - it's not just hardcore fans of the series that have problems with the game. Lots of things that casual players want are inexplicably absent. And lots of the things that the hardcore perceive as being sops to casual gamers really aren't - the items are, but we were never really aware of snaking anyway, and the radically different playstyles of karts and bikes lead very quickly to suspicions of unbalance. I expect that most playgroups are going to use one type of vehicle exclusively.
That's the real problem with MK Wii. No matter who you are, there's some element that seems to have been put in or left out for no other reason than to make you unhappy. It's very hard to justify a 9 for a game when there are so many things that you would have done differently. It remains very fun, of course, but it's hard to call it a wonderful product. I think an 8.5 is very fair. As a traditional title, it'd be worth a 9 or more if it had snaking and had been more skill-dependent. As a casual title, it'd be worth a 9 or more if it was more suitable for offline parties. These really aren't mutually exclusive, and I think it's really what most of both groups was looking for.