Miyamoto states that he didn't agree with the decision to make Pikmin 2 easier, and wants gamers to feel stress from time to time. The result of the change was a less strategic game, that Miyamoto doesn't want to repeat for Pikmin 3.
Awesome stuff! The only thing I didn't like about Pikmin 1 were the time limits, as it restricted the freedom of exploration. If Miyamoto can incorporate strategic, difficult gameplay that makes you think, and let us explore the beautiful locales, I'll be happy.
Pikmin 3 [Official Nintendo Magazine UK]