The common trend as of late, especially after Zelda U's reveal, is to say that realistic Zelda games sell more than stylized ones, using Wind Waker and Skyward Sword as an example. But let's look at things closer.

Wind Waker

Wind Waker wasnt only "a cartoony Zelda game," it was the very first Zelda game on the Gamecube, and the very first console Zelda game after Ocarina of Time and Majora's Mask. This was BEFORE different art styles for thier games (and console games especially) were the standard. People were incredibly HYPED for a new Zelda game, and there was no reason to expect an art style change. In fact, the art style of Wind Waker was kept secret from Miyamoto until late in development, because Anouma and the other developers were afraid of what he would think.

There's also the fact that the tech demo for the Gamecube was this:

http://www.youtube.com/watch?v=wBtAvX4Pkyk

So obviously, after seeing the art style of Wind Waker, many people felt betrayed and this would have possibly had an effect on sales for this game. There's also the install base of the Gamecube being less than the N64.

So yes, it seling less was partly because of the art style, but that was far more relevant to the time rather than overall.

Skyward Sword

Skyward Sword also wasnt just a "cartoony Zelda game." It was a Zelda game who's primary input method included Motion Controls. You know, the thing gamers have a HUGE bias against? The thing everyone thiks is a fad and wish would die? It's strange people think the art style had a bigger effect on sales than the motion controls. A lot of reviews even said the motion controls were the biggest and in some cases, ONLY problem with the game. So there's that.

Secondly, it came near the end of the Wii's life cycle. How much people realise that Majora's Mask sold less than Skyward Sword? you know what they have in common? Coming at the near end of a Nintendo console's lifespan. Gettig overshadowed by upcoming consoles and player fatigue setting in will definitely have an impact. Ever heard of Kirby: Mass Attack? No? Well there you go.

Zelda U

Zelda U is suffering from neither of those problembs. Art style change is now an established aspect of Zelda games, and it's coming in the middle of the Wii U's lifespan. Not to mention it will have a much more open world, something Zelda fans have been praying for for many years. This is something people want.

So no, I dont think the sales of the previous "cartoony" console Zeldas mean much at all.

Oh but they do affect sales! The non Windwaker style Link just doesn't do anything for me!

Wind Waker on GCN sold almost 5m. That argument is moot in my opinion. Also, the reaction to Zelda U was actually positive. I mean, the way they revealed it was terrible, but it's been very well received. Aonuma is actually happy with the fan reaction. "Cartoon" is here to stay. Thank god. How many open world games do we have that actually look like this? None.

I cannot stand either of their art styles I think WW was a pretty good game. but kinda disappointing for a zelda game.
but skyward sword is garbage it did not even feel like Zelda anymore.

I have very mixed feelings on the new art. I think they should have shown the trailer with Links traditional look.
But I kinda like the look they are going for. I do not like the enemy's design though. It looks to complex to be Zelda. and thats another problem I have in modern Zeldas. keep the fucking technology out. I like mine being set in what feels like medival times like OOT, TP

It sold almost 4 million, not 5. 

And Zelda U was well received by Nintendo fans, a bunch of Playstation/Xbox people aren't convinced about the graphics. I doubt this reaches Wind Waker sales, even. Just not a system seller. Cartoon Zeldas have never been, even if they have been the best (with the excepton of SS)

Did I really just spend all this time explaining why that argument doesnt make much sense for it to just come up on the first page

Was Wind Waker a system seller? Was Skyward Sword a system seler (Hint: no).

Was Ocarina of Time a system seller? Was Twilight Princess a system seller? (Hint: yes).

We've beaten this topic to death here. The sales data supports it, even if people here don't, and sales will once again reflect this (as sad as it is that people can't appreciate the brilliance of the artstyle).

The art style doesn't really matter.. it's what console the game is on that matters. Zelda sales peaked with TOOT and have been going slowly downhill since.

And I wouldn't consider the art style of the N64 games or Twilight Princess to be "realistic", they still feature a distinct colorful Nintendo art style without being too cartoony a la Wind Waker or the DS games.

The game is still gonna be beautiful regardless, and considering how popular the Zelda franchise is, I don't think the graphic style will drive away sales drastically.

Not "realistic", but with much less focus on brights compared to WW and SS.

TP came out when the Wii just came out, the Wii had sold less than 10m units at that time, and yet TP exploded out of the gate, ouselling WW in less than a year. It also moved a lot of Wii units, since it appealed to the hardcore audience who weren't completely convinced by the casual Wii.