As the writer of the story, I'll chime in and say I still think there will be a Just Dance or something from Ubisoft this year. It just won't be at E3. While it's not a stretch to take this news as "Ubisoft's winding down Wii U development," it doesn't guarantee that. It just means they won't be showing anything that is coming to Nintendo platforms at E3.
As of this minute, the only upcoming Wii U game we know about is Watch Dogs. A new Just Dance is likely, but it seems like Ubisoft won't be highlighting it at E3 if that is the case. That would be different from every E3 since Just Dance was first released, as those games usually have space at both Ubisoft and Nintendo's booths.
And for further details, as a Nintendo-focused site, we have always had a reason to check out Ubisoft's booth, even if it was like last year when we tried to find out specifics about Watch Dogs and Splinter Cell on Wii U while watching gameplay demos of the other versions. We don't have a reason to do that this year.
EDIT: Also, the wording is weird like "Nintendo games" because it encapsulated Wii U and 3DS games. The comment was a response to asking if there would be any Wii U or 3DS games at Ubisoft's booth this year.