I can see your points and agree with your general view. They have put quite a bit of effort in though, correct me if I'm wrong but, there's twice as many tracks in as other mario karts, 16 of which are from past games which is a bit of fan service as new players won't know them. All the online options sound good, racing against top ghosts, or ghosts just above yourself.
They were testing this in January with 2000 online connections a week, so they've obviously been putting quite a bit of effort in for that part (brawl was ~500 if I remember correctly).
Why?, because this is what Nintendo have started to do, they only push in the directions where they see profit now and good reason. As far as Nintendo were concerned they did enough with this title as you see it. That is troubling, when I see this game I cannot see the evidence of them striving to create a special game in the same way you can see it in Brawl and Galaxy.
Is there not a little bit of irony in this comment, given that Brawl isn't even out globally yet, and Mario Galaxy is less than 6 months old? Even games like WiiFit which a lot of people would consider as 'cheap cash ins' take a lot of effort and development, which you realise when you read the Iwata asks articles about it. I don't think Nintendo will be kicking out iterative annual updates like EA anytime soon.
Hopefully when the game comes out and people have got to grips with the options and tracks online there will be a pretty good setup to enable the best player to win consistently without it being a lottery. Hopefully it's not too slow either once you get good on it, it doesn't look it in the few videos I've seen, but I suppose they're only short clips.