During races I can pickup gift boxes and acquire tools to throw at opponents. I've noticed that they're always the same set of items and most often than not "anonymous/irrelevant", meaning that one tool or another I pretty much don't care. They are more like a side thing to me than a reason why I enjoy the race. I'd like to suggest these improvements (keep in mind I'm not a developer and I don't know how difficult each of these are to make):
- keep only a basic set of recurring power ups, then add another set depending on the current track. This is something that other games do, for example hedgewars
- build a list of power ups, and add a property to map editors to select which items should be gifted during a race and which not instead. Bonus point: let players choose the set of gifts before starting a race (or multiplayer game)
- add a kart-specific item to the set of power ups. For example, when I pick a gift box I can randomly get (item1, item2, ..., itemN, ?) with "?" being an item specific of the current kart. To avoid the problem of having to add new items to all karts, some kart might simply miss this "?" factor (and only get the default ones instead)
- replace some of the general power ups with others that match the attitude of the game characters (for example that suit a penguin, gnu, monkey, etc)