I can't comment on Sunshine but I know for sure Wind Waker wasn't done in a year. The game was originally going to be based off of the Space World 2000 clip, but then Miyamoto and Aonuma decided they wanted to go in a different direction only a few months later. This is why during an interview in the Spring of 2001, when Miyamoto was asked about how the new Zelda was coming along, he said it was progressing nicely and that Link looks really cute running around like he does.
Now at the time, everyone thought what Miyamoto meant was the game would be like Ocarina of Time and have both kid and adult Link. But when Nintendo shocked the world at Space World 2001, it suddenly became apparent that Miyamoto was talking about the Cell Shaded Link in Wind Waker.
Meaning Wind Waker was started sometime before Spring of 2001 and was released in Japan on December 13, 2002. So the game was in development for over 1.5 years. Of course big games like Zelda take a lot of time to make and so 1.5 years is still not enough time to finish it and that's why the two dungeons were removed from Wind Waker when it was rushed out.
Hell, Ocarina of Time was in development for over 3 years and they still had to cut things out of it to make it's Fall 98 release. This is one of the reasons why they made Majora's Mask because they still had a bunch of idea's leftover from Ocarina. This is pretty much the same thing they're doing with Mario Galaxy 2 now, using the idea's that they wanted to use for the first Galaxy but were unable to do.
In other words, Mario Galaxy 2 is this gens Majora's Mask. Take every crazy idea you wanted for the first game and just go nuts with the sequel.