The concept of Zelda 1 is what we need for the series right now, in my opinion. Freedom, combat focused (even with the items themselves), far less or NO puzzles, non-linearity, player growth (optional swords/armor/items and so on, maybe expand on this even further), high exploration that isn't limited by game progress, a huge overworld, higher difficulty, enemies everywhere, maybe even a second quest. Just imagine Zelda 1 on the Wii but with an overworld 3-4x as large with even more content and freedom placed into it..towns or even cities would be great..that is my ideal Zelda game, 2D or 3D makes no difference so long as the quality is captured solidly in either.
But Nintendo would never make another Zelda game like that. Zelda 1 and LttP are the only ones, and those are very old (but still great) games that deserve to be put on the scale of a modern day game. Skyrim would have some serious competition.
I'd like to see if Retro Studios or some other west developer could do it. Modern Zelda fans say the concept of old Zelda would be a flop, but that couldn't be further from the truth. Just look at Skyrim's success. An excact clone with the same size and length of Zelda 1 or LttP, for a modern day on a home console, may not sell as great, but that would be unfair and stupid. Zelda 1 is a 25 year old game..it could -easily- expand to the size and content of Skyrim and have a few old kinks polished up. That would undoubtedly sell loads (Zelda 1 sold to a cold market without name recognition and still sold nearing 7 million. Just as Mario Kart expanded its sales, so could Zelda), I truly believe that. Just don't go making it look like TWW or something.