With the release of the Pikmin short films on Wednesday, it seems likely that Nintendo is not finished with the franchise in the slightest. In Nintendo's latest Q and A session, Shigeru Miyamoto hinted at the possibility of what we assume to be Pikmin 4. Unfortunately, no details of any kind were released, but at least we have some confirmation that something based in the well-acclaimed series is coming.
Regarding Pikmin's future, Shigeru Miyamoto had this to say:
"Continually launching campaigns after the release of software will lay the groundwork for the next iteration of 'Pikmin' in the future. And needless to say, we want it to be one of the motivations for potential consumers to purchase Wii U. We are making a variety of different efforts." — Shigeru Miyamoto