Why would you put a lot of money into anything that isn't a lot superior to the hardware you already have? Such devices can be an addon these days - Kinect and Move showed it. You even can add functions like 3D over Firmware Updated and all that stuff.
What you can't do is getting more power out of old hardware. There you need an upgrade....a significant if possible so it lasts for 6-7 years again.The WiiU won't last that long and i don't think it will get supported the whole time like the PS4Nextbox will.Especially if the Next Gen Consoles make a huge leap from games before Uncharted/Gears 1 to The Last of Us and Halo 4. And the stuff that is getting the people interested into buying stuff is VISUAL Power cause this is the first thing you will notice.
We won't get that on PS4Nextbox either but we are much closer to this than with the WiiU and this is what i call "Console Next Gen" cause it will be a huge leap.
If you want that kind of visuals on a console then get ready to pay up $500+.
