It should come as no surprise if 3rd party ports of 360/PS3 games aren't as good on WiiU. Regardless of how powerful it may or may not be its a new console for the devs to learn.|
Plus confidence isn't high on the WiiU so expect ports to be unoptimised for the rest of the current gen. There's no point for them to spend the money at the moment.
Follow me on Twitter: @MrTom