Some people seem to believe that Mario Kart’s Wii incarnation has seen it descend from it’s lofty perch of arch technical racing game. There are plenty of good technical racing games available, such as Forza and Gran Turismo, where winning a race relies almost exclusively on skill. It’s not a new, or bad phenomenon that that’s not true of Mario Kart Wii.
The genius of Mario Kart has always been that it understands that actually, for a game to be most fun with a group of friends of varying abilities, it’s important that someone who’s barely competent can sometimes, with a big stroke of luck beat someone much more skilled. Mario Kart Wii keeps this and still makes sure, unlike many of it’s imitators, that over a number of races, the more skilled player will on average come out on top.
Some better design decisions could have been made. The perfect number for a game of Mario Kart is probably 6-8 and with 12 players there are just too many players with a really powerful present at any one time. Frequently seeing two players with a star active simultaneously feels wrong. This problem is further exacerbated by the new presents, which with the exception of the rather glorious personal lightning cloud, tend towards the over-powering, while adding little new in the way of tactical thought, but none of these things break the game.
Some of the later tracks remain tight and require technical skill; the new Rainbow Road is wonderfully finely balanced and even on some of the apparently more straight-forward trackes, as eurogamer point out, it’s allabout finding the next mini-boost, with a lot of room still available for eeking out extra fractions of a second.
Remarkably the online play really works well. The needless complication of friend codes and the fact you don’t have visibility of friends during single player are unfortunate, but the general match-making is simple and smooth and the racing is in general pleasantly free of lag.
The DS version, which I’ve been playing almost continously for close to 2 years, has rightly been held up as a return to form after the awful Double Dash and Mario Kart Wii, while perhaps taking as many steps back as forward, is starting from such an advanced position that it’s still a remarkably joyous game.
Phil Wills' Approximately Honest Blog 
Who would think that the Mario Kart Wii was actually a driving sim in the first palce.