That's not how generations work
The only difference here is that we don't know what Sony and Microsoft are doing yet, but the Wii U IS the first 8th gen home system, since it's Nintendo's new system after their 7th gen system (the 3DS and Vita being the 8th gen handheld competitors this time). System power and even the use of different innovations has nothing to do with what generation a console is in. I think/hope both Sony and MS will release their 8th gen consoles this year, and I can't wait to see what they'll both do.
I think that, after maybe the next generation, the concept of "generations" might die off altogether, but we'll see