Without question the 3DMario game and Retro's next title. Although from the outset with the 3D Mario Yoshiaki Koizumi said that he wasn't sure if it would be on Wii U or the next system, and that was 3 years ago. By then Nintendo knew the system was flopping hard and titles that were envisioned for Wii U were quickly being shifted. They've worked on Switch for 3 years as well, so you could say they moved or started out for switch. Either way, if Wii U was more successful they probably would have been on that system. There are probably another title or two that went through a similar process.