This is identical to the Wii Fit Plus version. No extras on the Wii U.
It tells you this in the tutorial when you first pick the game, but the key to "nice shots" is all in how much weight you shift from back to front when you swing.
Timestamps:
0:00 Approach Shot
4:59 Iron
9:04 Driver
Playlist: • Wii Fit U (4Star Ratings)