The system is hardly underpowered, and blaming Nintendo for devs not using it to its full potential is like blaming an abuse victim for being abused. It's not the fault of the abuser at all, the victim deserves to be punished for whatever.
And remember, they have taken suggestions. Why do you think they're pumping money into R&D, why do you think they're working on proving the potential of the system with upcoming titles (such as the NFC ones to be shown at E3). The system itself, functionally, is no different from a DS. If that system had as much shovelware as it did, including some devs using it quite uniquely (as seen in games like The World Ends With You) why can't they figure out how to do the same with the GamePad?
They're always blaming the GamePad or weak specs but do nothing about it, while indie devs embrace whatever limitations the system may possess and thrive within it. Nintendo doesn't deserve a service that shows half-assed efforts by devs who really don't want to support the system and only do so to say they did, and then pull support when their inferior versions don't sell as well as the full-featured ones. We're lucky that CoD: Ghosts just got the Free Fall map on Wii U, considering other devs that pull all DLC (as seen in Arkham Origins) or don't even offer it for the system (as seen in AC4).
There's no reason the system can't handle the full versions of these games. Devs just don't want to put in any effort, and that's hardly Nintendo's fault. The system is anything but underpowered, and any claims that it is are just excuses so no work has to be put in to releasing a game as full-featured on Wii U as it is on other platforms.