Microsoft have made a big media splash regarding Natal, their new motion control system for the Xbox360 introduced as a ‘me too‘ against the Nintendo Wii. I expect that, similar to many of their previous efforts, once the media hubbub dies down so will interest from both the consumer and developers, but that isn’t that biggest problem they have.
The major issue with Natal is that developers are not required to support it, and if they aren’t required to support it they won’t (once the media attention that might help their product dies down). Including support for Natal will also require additional development time and money, something that is already a premium.
This is the complete opposite of the Nintendo Wii, a market which Microsoft are clearly desperate to capture (and they won’t capture any of it with this effort), because the Wiimote is the only form of control available on the Wii and thus everything must support it, or some variation of it.
My prediction: Microsoft’s Natal for the Xbox360 will be supported by products attached to its launch but will see little to no support afterwards.