RNG ruined this game. Even if you drive perfectly, you have virtually no chance of winning if you get hit by a blue shell near the end of the final lap. The game includes no way to prevent a blue shell, further removing skill required to come first. You can also get combo'd by a string of items afterwards, further securing your loss. It's a frustrating waste of time trying to get Gold Cups in Grand Prix. If you enjoy playing slot machines in casinos, you'll like Mario Kart Wii. Some luck is fun, but too much luck is not. It becomes mindless and stupid. That's what Mario Kart Wii is to me. I rather flip a coin and guess the outcome than play this game.
Bikes were a good addition. Although they were unbalanced and obsoleted karts, which mattered more in multiplayer. The wheelie ability added depth to the game. You can speed boost, but can be risky since there's a deceleration punishment if you get hit during the wheelie.