If it does come out next year and it is as good as we're all hoping it will be I don't see why it can't push 3.5-5 million.

I know the install base will be low, but there are a lot of people who will buy the console for Zelda alone that may not have it now. As people have stated, Wind Waker sales were fine and that had a low install base as well.

http://m.neogaf.com/showthread.php?t=963700&page=1

Obviously its a possibility since this is probably going to be Nintendo's lowest selling home console. But I think it could avoid that fate. Being the only (or first) new Zelda means it will be better positioned than Majora's Mask or Skyward Sword (released on a huge install base but at the end of the console's lifetime when I think a lot of the audience for Zelda had moved on). The Wii U will have a low install base but a lot of those people will be interested in Zelda, if it can keep the hype for it building nicely, deliver a high quality game and avoid doing anything that will alienate a lot of the fanbase, it should reach a very good attach rate, and hopefully enough to pass Majora's Mask on N64 and maybe even Skyward Sword.

LF? It should be bigger.
For one, by the time it releases the console will be 12m+ sold, for 2, it looks amazing, 3, IF advertised & hyped up enough America will push 2m sold.

I´ll say 2 m... by the end of 2015 of course, this is going to be huge, clear like water.

Comparing Zelda U to Twilight Princess would be a better idea! Furthermore, SS sold only 3.8 million because it came out late during the Wii's lifespan and because it forced you to use Wii MotionPlus.. Zelda U obviously won't suffer from such issues!

 Well, I'd like to think that Zelda U will sell decently due to it being the first true HD Zelda game! 

I guess it is the first Zelda game in a while to technically modern since windwaker. The Wii U isn't close to the PS4/X1 but dimishing returns means it might not look so dated come November and that will help it sell to a newer audience and old fans. The lack of appeal in the Wii U hardware is still biggest factor for me though, we'll see how cheap the system is come the games launch. 

it will be the best zelda seller in history

Might not sell as well, but is looks like it will be a fantastic game. I think it will sell well enough considering most games aren't selling as well as they used to mainly because the Wii U itself isn't selling as well.