Mario Kart Wii has been accused as being dumbed down for casuals.
The great thing about Mario Kart Wii is that it gives you the option of having drifting be performed automatically or manually. Even better is that manual is better in most circumstances because it gives you the drift boosts.
In Mario Super Sluggers, you can have fielding and base running be performed automatically or manually. In this instance as well, manual is better because the A.I. is a bit single-minded.
This is the kind of thing I would like to see in all of Nintendo's games. Include
options to customize the game to be simple or complex, possibly giving the more complex way a bonus or two because it's more difficult. This kind of thing can encourage people to become more skilled at a game; start out playing it the simple way, and after you get the hang of that switch to the more complex way. This would also allow you to play multiplayer games with people who have never played the game before and still give them a chance to win.
I hope the Mario Power Tennis Wiimake has some such option. After you learn how to hit the ball correctly in Wii Sports Tennis, there's nowhere to go from there.