ZombiU highlighted a sadly lackluster launch line-up for the Wii U, unless you wanted more New Super Mario Bros. While the game enjoys a very loud and loyal fanbase, the profits and earnings through the title are sadly not enough to convince Ubisoft that ZombiU needs a sequel.
In an interview with GamesIndustry.biz, Ubisoft CEO Yves Guillemot stated that betting on the Wii U launch didn't work out so well given that the popular title failed to make money. There is apparently no plans, or desire as the interview says, in the halls of Ubisoft for a sequel.
I don't really blame them. There are enough zombie games in the world, and one ZombiU experience is enough for me. It's a solid game with a lot of great ideas and above average execution. I am kind of happy that the team is not nailed down to the IP. Put them to work on something else and move forward.
Ubisoft also took a bet with a launch on the Wii as well with a wonderful title known as Red Steel. You all remember Red Steel, yeah? Tell me again that ZombiU is an under-performing game, and I'll happily point you to that alternative.
The reputation for Ubisoft first-person shooters at on a Nintendo console launch combined with a horribly generic title and poor console sales, and you have three solid reasons for the game's failure. Don't blame the quality, at any rate.