Nintendo is working with Tecmo-Koei to have The Legend of Zelda made into a Hack and slash game and Retro reinvented Metroid as a First person shooter. What other Franchises could jump game styles and still retain their core ideas?
Maybe Fire Emblem could become a standard JRPG in the vein of Suikoden with its multitude of characters and would still have some strategic elements of the previous games. Hopefully the upcoming crossover with Shin Megami Tensei will go in this direction.
Another possibility is Kid Icarus becoming a pure on-rails shooter. The flying segments of Kid Icarus: Uprising were really impressive and had exciting gameplay, but once Pit touched the ground the controls fell apart and it spoiled a great game.
So which Franchise would you like to see dabble in another genre?