This could go either way: Either the Wii U is essentially current-gen technology (and as such, will be left behind when the next Xbox and Playstation launch), or it's unusually powerful and will have some lasting power.
Now, when the Wii launched as a "weaker" system, what was a secondary effect of it being essentially a last-gen system? Prolonged life of the PS2 and added boost to PSP multi-platform games. Multiplatform games for the Wii were relatively easy to port to or from the PS2 and PSP, which kept the PS2 alive longer and likely made it easier for developers to simply add the PSP to a list of systems with which to share ports.
It's entirely possible that the Wii U simply prolongs the life of the current generation by a year or two, which I would support completely. I want this generation to be COMPLETELY exhausted by the time the next generation rolls out, that way we developers can be more prepared to move on, gamers can maximize the value of their current systems, and the tech leap to the next generation can be as incredible, impressive, and necessary as possible.
Of course, it's limited power could leave it in the dust within two years when the next Xbox and Playstation likely launch. I don't expect the new systems until 2013 at the soonest. Probably late in the year. Microsoft's sales are actually up over this last year, so they have no reason at all to jump to the next generation right now. The PS3 for that matter, is holding pretty steady and doesn't need a replacement any time soon.
Part of why I think the Wii U is potentially only on-par with the X360/PS3, besides persistent rumors, are the facts that as usual, Nintendo didn't release hardware specs (just general console information, like it's size) which means they don't want people focusing on the "weaker" internal hardware. Also, the system isn't much bigger than a Wii, which means that it's likely housing compressed or "optimized" current-gen hardware, not unlike when the PS2 Slim launched housing the same PS2 hardware in a substantially smaller package. If the Wii U featured a drastic leap forward in hardware power, it'd likely be a helluva lot bigger. Like the size of the Xbox 360 S at least.