The problems the Vita and Wii U have are the same. The things their predecessors did well are either now done better by competitors or are not important anymore. The 3DS took over the gaming niche the PSP occupied and the portable media player market moved on from the PSP towards smartphones and tablets. The Wii U doesn't really give us anything to entice current Xbox 360 and PS3 owners at the moment and it doesn't represent a no brainer upgrade for existing Wii users, you can say that it is either not good enough or that its competitors have got better.
Given enough time the Vita and Wii U will probably find their feet if their competitors sit on their hands. If the Wii U looks like it is struggling against 8 year old consoles then how will it perform against the latest from Microsoft and Sony? If the Vita is starting to have its lunch eaten by smart-phones and tablets, their rapid evolution will ensure that by the time the Vita starts to become relevant it'll be irrelevant if you get what I mean.
Tease.
