"If done properly" then there's really no reason to say no. Four Swords is already a thing, and considering Aonuma's comments in January 2013, I think we can expect to see some kind of multiplayer aspect to Zelda Wii U.

something like dark souls

Is everyone ignoring four swords? anniversary edition is pretty darn fun for 3ds/dsi; and keeps the zelda concept of exploration and puzzle solving in a multiplayer enviornment, of course with both cooperation in competition.

Another heavily underatted multiplayer mode in zelda was the phantom hourglass force gems mode. This game would be great for wii u with second screen and allow for one to draw out the path for the phantoms and would really capture the idea of asynchronous gameplay.

I'm really confused by this topic. Zelda multiplayer has been done heaps of times.

Four Swords
Four Swords Adventures
Phantom Hourglass
Spirit Tracks

Then the spin offs:
Nintendo Land
Link's Crossbow Training
Hyrule Warriors

And the companion option in Wind Waker.

i've really wanted this actually. 4 player online co-op adventure. If everyone splits up the game can be finished in almost 1/4 the time, but is ALOT more challenging, Sticking together would make the game easier, but take much longer since your covering less ground. Also, if a one particular quest hasn't been done, then certain others cannot be completed. So you could be on your own trying to survive an onslaught while begging your comrads on the other half of the map to "hurry or i'll die!". Lastly, this is a spin off game. A parallel sequel to a major Zelda game. Only secondary characters from the major zelda games are playable. Almost a behind the scenes of whats going on in hyrule while link's not around. Hyrule warriors actually gave me a glimmer of hope for this to happen. It never will though. Not really. Not my vision anyway.

I don't think it means multiplayer. It must be about a feature using Miiverse, like WW HD.

I think it could work. I would still rather the focus be on single player, but even a little multiplayer on the side could be good. I actually enjoyed the multiplayer in Phantom Hourglass. Fun, small diversion.

I'd be down. It would be cool if there was some sort of Dark Link 1v1 or arena mode kind of like in ALBW, but with live online players. That way players can play as the character they're used to against others on an even playing field without betraying the canon. 1v1 on cool little boss arenas, or something like a 5 player death match in a larger map arena. Obviously everyone will just look like Dark Link to you.

A co-op mode with a friend playing as Zelda or again as Dark Link would be cool too, if it doesn't effect the frame rate negatively. They could help you with post game boss rushes or with unique co-op only side dungeons. There is so much that can be done to extend playtime.

I see no reason why online multiplayer can't fit in a Zelda game, and the only reason I don't want local is because it may lower the framerate.

EDIT: They can also have four player online co-op with 4 different colored Links like what was done in Luigi's Mansion 2.