What with the Harry Potter books and that Sorcery game for PS3, a witches and wizards sort of game in the Pokemon world's past history would be neat. Wonder if it should Harry Potter the wands though, like with a "yew with a Rapidash core". Spells could be Pokemon attacks and obstacle clearance.
Another spinoff if I'd like to see is a pure Pokerus and would play like an Advance Wars Pikmin cross on a Pokemon flesh battlefield. The type of Pokemon you are on (Jolteon, Slugma, Muk, etc) would have hazards (random sparks, popping gas bubbles, teleports). The Pokerus themselves would be in different colors (how many, not for me to say me thinks), different types (more like the ALIGNMENT idea of Earth, Wind, Water, Fire, Heart (LOL), Dark, Light).
Show us what the Pokerus looks like, Game Freak. I'm tired of thinking of the "Welcome to Wal-Mart Smiley Face".