How this will be received will depend on a few things ...
How well it works; if it doesn't make a (noticeable) difference in the games that use it there will be little or no value for most consumers. With that said, the #1 complaint I have constantly seen on this site from HD fans bashing the Wii (beyond graphics) is that it doesn't have 1 to 1 controlls; if this is implemented well and interesting games use it people will really like it.
If they incorporate it into new Wiimotes ... If they're releasing this add-on so that people who currently own a Wiimote don't have to buy entirely new Wiimotes (and every new Wiimote includes this after a certain date) this could be a seemless addition.
How they sell the WiiNubbin ... if you buy a game with 4 WiiNubbin's for $60 it will (probably) be low enough cost that many/most Wii owners don't feel ripped off.
