Nintendo said this before and they’re saying it again. There’s more games in development for Wii U then what they’ve already announced. This is something they reiterated in the recent investors meeting. Here’s what Iwata said exactly:
These are the already announced Wii U titles that will be released in the fiscal year ending March 31, 2016, and there are also unannounced titles that are not listed here. Among these titles, there are games that actively utilize the Wii U GamePad, including several we showed at E3 last year that are considered part of the Wii U GamePad utilization project led by Mr. Miyamoto.
With all of the recent rumors of unannounced new games from Nintendo and publisher support for Wii U it’s going to make for an interesting E3. Luckily, we’ll be getting a lot more information in the very near future!