WiiU was underpowered when it launched. Even if someone had utilized it 100%, it still would have been behind compared to the Xbox360 and PS3. 720p only when the Xbox and PS2 were already supporting 720p and 1080i was also a bad choice.
WiiU was just a bunch of bad choices combined in a single product. Bad hardware choices, bad marketing, bad name, requiring the massive gamepad for console setup, etc.