if they can utilize the Gamepad as well for Zelda U as they did for ZombiU then i would happy with it. i haven't played a game that has utilized the Gamepad that well in a while. but if it's any less i will be a little bummed.
i generally like hard games and bosses, i feel like if most games were harder i'd like them a lot more. the harder the game the better i feel about advancing and beating it, although i haven't played a hard zelda game since i beat ALTTP. i enjoy harder boss battles. its the reason i like Dark Souls.