For something peaking at just 40W, and with such a small form factor and relatively low price, i definitely wouldn't call the Wii U "underpowered."
It just does something different from the competition.
We've yet to see what the PS4 looks like at all, but it's pretty safe to bet it is both considerably bigger and more power hungry than the Wii U, on top of costing at least $100 more.
If things are "underpowered" because they are balanced differently as a product, then everything is underpowered compared to Pixar's new render farm and the super computers simulating wind tunnels.







