It is cliche but "power" isn't so important but what devs do with what is available. If Nintendo is just going "Here you guys go" without further shepherding then it is DOA.
Power was always important. There were always graphic and power wars even in the times of Atari and co. More power also means new mechanics, new ways of playing, new possibilities.
Why wasn't EA making these complaints about the Wii then?
They did. And what was the Wii EA support about? Yeah they still got their madden and Fifa but beside that? Also remember the legendary "2 duct tapes together" quote? That back than came also from one EA employee.
and even with that the Wii did fine.
Yeah because it had appeal. It had a system seller called Wii Sports and motion control which was easy to get for people who never played a video game before. The Wii U has nothing of this and this could be very well end up as Nintendo's biggest failure to date. Mabye even Nintendo's downfall.
I don't know about all that downfall stuff but I do agree that Nintendo failed to provide a Wii Sports equivalent to help people understand what this system actually is. I think brand confusion might be more in play that this however. I can recall the handful of times I was at a Target or Best Buy and explained to parents what the difference between a Wii and Wii U is or that Wiimotes work with the Wii U (that packaging doesn't help at all) I believe this is one of the more major things Nintendo needs to fix.
They can not fix it anymore. It is done. They can not suddenly change the name. The Wii U is done for and nothing really can rescue this device. It was a total misconception in terms of hardware, system and marketing.