Gamecube is my favorite of these systems, but two of my Gamecube favorites are getting retail versions anyway (Tales of Symphonia and Harvest Moon/Story of Seasons: A Wonderful Life.), and Resident Evil 4, FF Crystal Chronicles, and Mario Sunshine are already on it. I'd rather have retail versions of games like TP, WW, Metroid, Fire Emblem: Path of Radiance, SoulCalibur 2, and Star Fox Assault than have them tied to a sub.
GBA would be cool, too, but the one GBA game I really want, Mother 3, isn't likely to come to Switch.