I've never really heard of people hating Wind Waker as a whole, more like complaining about things like the artstyle not being of their taste, the sailing being tedious or being to easy. So far, those points have even been mentioned here, so if you read the posts before this one, you'll probably know that already.
I think those complaints are valid actually, but not really game-ruining. MW7 has made some good points like:
A second criticism I have is that the islands are way too far apart. The ocean could have been a third of the size and not have felt cramped IMO. It takes ridiculously long to travel from one edge to the other. Sailing was a great idea, but I think it wasn't implemented as well as it could be because of the distances between islands.
While I don't completely agree, I think the islands being too far apart is definitely something that could've been worked on. I think it actually got tedious more than a few times, but I guess all the Zelda games have parts that someone will probably find tedious. That said, I also liked the sailing element and think that it's not really a game-breaker. I've seen far worse mistakes in other games including bugs, bad camera angles, broken controls, you name it. If anythinhg, I think it helped make the world's scale feel massive and I think that alone makes it a minor flaw in my eyes despite the tedious parts (like the Triforce quest, even though I thought it was a pretty good excuse to fool around).
I like it for how vast it is and I actually enjoyed all the sailing which was annoying for some. I was on a Zelda hiatus for a few years as well so I never experienced that let down some had by seeing a preview of a realistic Zelda one year followed by a cartoony cell shaded look the next year. The funny thing is my wife got me back into Zelda and it was with a copy Wind Waker that she owned that brought me back so I will always have positive memories of it. Though I prefer a more realistic look the animated art direction of Wind Waker is fun and entertaining. The biggest plus is that it takes the longest for 100% completion which in my book is a good thing. So while it's not my favorite it is far from being my least favorite.
Same here on the sailing and the artstyle, you know... maybe that's why the style never really bothered me. I was just like 7 when Wind Waker came out, after all. I wasn't aware of shows like Spaceworld or E3, let alone follow them. Not to mention I had only played Ocarina of Time (which I hadn't even finished at the time
), which means my experience was pretty much nothing. xD
I like the fact that they change artstyle, though. I'm one of the people that supported Skyward Sword's style from the start not because it was realistsic/cartoony enough for me, but because I appreciate when Nintendo tries to think out of the box and surprise everyone. After all, the Zelda formula lends itself to changes like that, doesn't it? Like it was chameleon or something: It might change and manage to look or feel different, but deep inside, it's still familiar.