Having more power doesn't always equate to the need to show "realistic" graphics. More power lets the devs do more with the ai, scale, effects, ect. I think Nintendo will be fine because people who love Nintendo love them for their games NOT because they are the pinnacle of graphical prowess.
That being said it would be much easier for 3rd parties to make games for the platform if it was closer to the PS4/720 in terms of power.
Basically I really see no negative in having more power. However there is some concern for having something underpowered (not saying the Wii U is, just in general)








