In my opinion (I'm going to get hate for this) Wind Waker is almost a PERFECT Zelda game. The graphics made it very child like which was fine with me because when I first played it I was around 8 years old. The difficulty, many say the game was too easy, but if you do look at it closer it really isn't that easy. From fighting Cyclos to fighting Giant Octopi. The combat system was fun and easy to use. Windfall Island(and all the other islands) were just simply amazing, designed perfectly and had the perfect NPC's on them. Overall I am happy with this Zelda game. It is my favorite game, (Tied with OOT and MM).
EDIT: Another thing I forgot to touch on, exploration. The aspect of sailing in this game was perfectly done, it was fun and easy to do. People say the game is too short. Well it really isn't seeing as there are SO MANY side-quests available for you to do. Let alone getting all the item upgrades, Wallet upgrades, Heart Pieces, secret dungeons. This game is amazingly long.