No readily identifiable mascot or main character.
There you go. That's a necessity for platformers or games that target a younger audience. Pokemon would never have been as big without Pikachu being plastered everywhere. Sony actually tried very hard to make Sackboy identifiable and it paid off.
You want your new cartoon-style IP to take off? Make sure you have a unique character, make sure you give that character a brandable name, and make sure you say that name over and over and over in your media. In effect, give your IP a name and a face for people to associate your game with, which gives it a personality. I said the same thing with Pikmin, that it would have sold much better if it had a Pikachu character or if the leader was given a memorable name and personality and promoted heavily.
