Unfortunately, I'd say once the PS4/720 axe falls, Wii U has had it.
Vita may not be a smash hit, but it has exactly one competitor in the handheld market. It will never outsell 3DS but it appears that it has some chance of gaining traction.
If Monster Hunter, Super Mario Bros, and Dragon Quest can't sell the Wii-U then I don't think anything will. Not even a Zelda game. And a DQ game that does that badly in Japan? They won't even bother releasing it outside of Japan, and that would be a wise decision. Only way they could salvage DQX is to maybe port it to 3DS and hope for the best.