I'm not sure whether difficulty levels could work in Zelda. I say this because the game's difficulty comes from many different factors, such as puzzles, enemies, time limits, limited platforming etc. Contrast this with for example a 2d fighter, where enemy AI is mainly changed. If there was an easier difficulty setting, Nintendo would have to redesign dungeons, or at least add in some extra ladders, hints and make platformers bigger as well as adding more health.
I would rather if the main game was kept fairly easy, but there were optional dungeons that made Zelda II look like a pussy.
Or alternatively, they could just use the 'Super Guide'








