Wrong. As a whole, Skyward Sword is by far most challenging than OOT, Wind Waker and especially TP combined.

sales are great actually, and the fact that ocarina is selling as good is pretty weird, probably because it's one of the only good games on 3DS outside Japan

Well, this requires a proper comparison! How well is Skyward Sword really selling? There's far too much stuff said without any proof of it here.

These are the total sales of the titles in the different areas.

Now, how much can we expect Skyward Sword to sell?  I'll start off in Japan, as that's by far the easiest.

It's at 312k after 7 weeks, with the last 2 of those being 10k.

After 7 weeks, Wind Waker was at 691k, and sold 10k in the 7th week. It went on to sell another 190k, ending at 885k.

After 7 weeks, Twilight Princess (Wii only) was at 358k, and sold 18k in the 7th week. It went on to sell another 230k.

Seeing as SS sold a lot less in the first 7 weeks than WW, and had a far lower week 7 than TP, we can't expect it to do quite those numbers. It's also released later in the generation, hampering them further. Everything point to another 100k or so being all it gets here.

0.4-0.45m in Japan, the series by far lowest.  Still, that's a trend the series has been having for two decades now, and hardly a shocker.

In USA, it's at 1.4 million after 7 weeks, and sold 22k in its 7th week. After 7 weeks, Twilight Princess (Wii only) was at 906k in USA, and sold 44k in the 7th week. SS sold 25k in its 6th week, though, so it's hard to judge this without knowing if the 7th week was an unusual low or the trend for the future.

TP went on to sell a total of 2.2 million more in Americas after week 7, but a lot of that was from being on the market a long time, and SS won't have that. TP sold 360k in 2009, 350k in 2010 and 570k in 2011 (courtesy of Kai Master for doing the calculations), and a large amount of that was probably in Americas.

Frankly, I think SS will be hard pressed to do much more than a million more in Americas. It doesn't have a long time left to sell for, and it's not looking to sell all that well. 800k-1.0m in more in Americas, making for 2.2-2.5 million in Americas. The second lowest since the series went 3D.

In Europe, it's a whole other story. It's at a million after just 8 weeks, and it sold 26k in its 8th week. For a compaison, Twilight Princess was at 540k after 8 weeks, and sold 18k in its 8th week. TP went on to sell 1.3 million more. As with Americas, a bit of that was legs for year 3 and 4 - years Skyward Sword won't have - but SS is the first Zelda to properly catch on in Europe. I'm expecting a far stronger year 2 for SS in Europe than TP had. In fact, I don't think selling about as much as TP did from week 8 and out is unreasonable. It could even do more than that, but I'll have to see some more numbers before I predict that. 1.2-1.4 million more in Europe, making for a total of 2.2-2.4 million in Europe. 

4.9-5.1 million in the 3 major areas. Then, there's the whole "other" bunch of numbers. We don't really know a lot about those areas, and they'll be incredibly hard to predict. Still, they're at 500k already, which is quite high. 400-600k more seems the safe bet, as I'm predicting a double overall. This one is rather baseless, though.

Worldiwide, we're looking at 5.4-5.6 million plus whatever more is sold in "Other". Add in a 400-600k, and a 6.0 million is roughly my prediction.

Now, there's a fair bit of assumptions here, so there will probably be people disagreeing either way. I would think, though, that it should be difficult to disagree with more than a million from this number, and even that seems quite extreme.  That means that we're pretty definitely looking at Skyward Sword becoming the 3rd best selling console Zelda, roughly tieing with Twilight Princess (Wii only) and right in the middle of Ocarina of Time and Wind Waker.

Not a failure, not an amazing success. Although far more of a success than I predicted, which I believe was 4.5 million.

Tbh I've been playing Zelda since the first game and don't have a problem with Aonuma, imo he's done a great job with the series the Zelda fanbase is filled with people who want the series to become like another series (e.g Elder Scrolls) which is a horrid notion or people who want something geared more towards their own individual preference which is impossible given how Zelda has to cater to an entire fanbase which is why not everyone is going to be happy. SWS is easily among the best games I've played since I started gaming and I quite like the direction the franchise is going on shifting the focus to the type of adventure you have.

Ok, maybe i'm too good.

Let me doubt it.

One big mistake on Nintendo's part was making the M+ bundle a "Limited Edition". The bundled version should have been widely available, because having to buy an otherwise useless accessory along with the game surely scares buyers away. It just makes no sense to me, they should have used the bonus CD as incentive to drive preorders of the first shipping, not the M+ controller, since it is essential.
Other than that - what people already said, OoT3D is a classic, on a hot new system, bundled with a collectible Zelda edition of the system.
But still I am really sad about SS's low sales, people just don't know what they're missing.

I think the limited edition is only the gold Wiimote, and now it will be available in budle with a white Wiimote.

That might happen, but as a matter of fact the bundled version was hard to find and expensive in the crucial first months. Nobody likes buying a gimped version, I know I wouldn't have bought the non-bundled one. 

How much did Ocarina of Time sell on Virtual Console? Does anyone have figures?