I've been playing Mario Kart Wii a bit more now and I have to say my initial excitement has come down substantially as I've been playing more. Unfortunately, this has started reminding me more and more of Mario Kart 64 especially in the races.
What bothers me most is this: The outcome of the races has little to do with how good you actually are but whether you're fortunate enough NOT to be hit by a bomardment of blue and red shells in the final lap. And since the blue shells can reach you no matter where you are leaving your opponents behind has absolutely no meaning. Similar to Mario Kart 64, it all comes down to the final lap which is just annoying to me.
I also think that, in general, there are too many 'events' taking place during races. I.e. there's way too much lightning, POWs, ink squirts, and shells. I find it quite disrupting for the actual racing which - so far - I found to be far more fun in the original where you had the odd bolt of lightning (making it a special event and actually valuable) as well as a reasonable amount of shells, bananas and stars.
I also think it's a real shame that you can't pick the number of players for the competitions (e.g. battle mode). The AI isn't particularly good (at least that's my impression), and it can be frustrating driving around the rather large arenas at times seeing that your team is just losing and losing and there's nothing you can do about it.
Let me say I REALLY want to like this game. I simply bought it when I saw it in the store. I'm going to keep on playing, and I hope that I'll find the races in particular to be less arbitrary in their outcome than I do now.