I'd like Zelda and Link to both be playable.
I'd like them to either go much much darker, or back to Wind Waker style.
I'd like a heavy character focus. Midna was great, but other than her TP lacked interesting characters, and Castle Town felt lifeless.
Difficulty... eh, I'm fine with it. Zelda has never been difficult. I can still beat any 3D Zelda game without ever dying. Including Master Quest, but more puzzles is always a plus.
Step up the bosses... I'm envisioning Shadow of the Colossus style bosses, and yet even bigger. Like a final boss who's a huge city-sized dragon, and beating him is one giant puzzle.
New items, with multiple uses. This has been mentioned before, but items need to be able to be used for an extensive period of time... not just in the dungeon they are found. And yeah, the bow and bombs always are, but how about some other creative stuff? Bring back the Roc Cape and let's see some cool jumping puzzles in 3D. Let me equip multiple items so I can use them in conjunction (TP did this a little bit, which was cool. Expand on it).
Bring back magic. Not sure why but magic has sorta disappeared from Zelda since it went 3D. Yeah, it was used a LITTLE bit in OoT, MM, and WW, but not much. I'd like to see it become a major part of the franchise again. Maybe make Zelda a spellcasting character with a bow. Should add some interesting gameplay diversity.
