9. The Muppets
Disney acquired the rights to The Muppets from the Jim Henson Company in 2004; two years after the first Kingdom Hearts game had been released. With characters ranging from the memorable (Kermit the Frog and Miss Piggy) to the humourous (Statler and Waldorf), the addition of the Muppets to Kingdom Hearts III would be effective from a marketing standpoint, though the fact that they inhabit our world would make integrating them with the Kingdom Hearts universe somewhat difficult for the games writers. Nevertheless, with the range of characters and potential storylines available, featuring them in some capacity has to at least be considered (I'm thinking something along the lines of finding them in different worlds to reunite them all, akin to the 101 Dalmatians quest in Kingdom Hearts I).