I'll draw my conclusion from the things that have been confirmed.
1) IBM CPU that is not Power 7. Info is still vague. I doubt it will be anything weaker than the Xenon.
2) AMD GPGPU. At this point any would be better than what's in the PS3/360.
3) Slightly more than twice the amount of RAM for game development than the current consoles. It has 2gb, but 1gb will be for devs.
4) WiiU can do full 720p with 4x AA or 1080p native.
WiiU is, at most, 3x more powerful than current consoles.
e=mc^2
Gaming on: PS4 Pro, Switch, SNES Mini, Wii U, PC (i5-7400, GTX 1060)