It may look like a game for kids, but it's still definitely worth playing!
Fortunately, Wind Waker just got better and better, and I ended up completing the game with 16-17 hearts, meaning, I actually thought it was worthwhile spending a lot of time looking for heart pieces. The game certainly grows on you, and if you feel uncomfortable with the kiddie presentation at first, like I did, you will later begin to admire the game's graphical style.
One thing I didn't like about this game was the sailing. Especially when you still do not have the ability to warp to different locations on the sea map, riding through the almost completely single palette blue sea can be rather boring. To be able to find most of the heart pieces, containers, upgrades, and crucial game objects, you need to do a HELL of a lot of sailing. Without the sailing, game time would have been cut at least in half. I'm not saying that I'd prefer the game to be shorter. My point is, a lot of this time is wasted on the sea which could have been spent doing more meaningful gameplay had the game been designed differently.
Of course, the sailing being boring just might be me. My nephew says sailing is his favorite part of the game. I just think they could have done away with such long sailing times, and instead made the levels a lot longer, or added more of them. Some of the levels were just way too short for me.
Overall though, it still is a very good game. Very well produced, obviously because it's Zelda. Great graphical style that will certainly grow on you if you don't like it at first. Nice and very fitting background music, some of which got me whistling to their tunes. Simple and solid controls. Easy but satisfying puzzle solving and enemy/boss fights.
It's just SO Nintendo, if you know what I mean. And that's not a bad thing.
I don't know if it's for everybody, but this game is definitely something I would recommend for anyone with a Game Cube, and especially to Zelda fans.