They won't need full support or anything... and clearly they're already looking beyond the conventions of gaming.
They will need to clearly differentiate Natal and Natal applications, from every other xb360 software on the market.
In fact, they should pull the cameras off the shelves now and give rebates to those that have cams to buy Natal.
They need this to be super simple for people if they want to bring in any of the Wii market.
As an add-on for the existing xb360 base, yeah, as hardcore gamers we like the interface for non-gaming activities and will buy it for that purpose, but to capture the Wii market, it will need to be cheap, simple, and have enough on offer for people to buy in.
This base has already seen Wii. To us, obviously it offers more, but the only obvious benefit to potential Wii buyers is the fact they won't have to buy waggle remotes for every one (3) and nunchucks (3).
It needs support from games like Madden, FN4, Tiger Woods, etc ...
It needs to show and prove that not only does it outdo Wii in more accurate waggle controls, but it also offers a better gaming experience with richer AV and just as expansive library for diversity.
It will take a lot to unseat Wii, but it can be done. The tech is far superior in every way, but it needs to present that message clearly to consumers to maximize this difference and superiority.
If people see this as an xbox360 ... they have little reason to get excited. They don't want xb360, or they would have one. Wii is still showing strength in pulling consumers.
Putting a different name on the platform (even a different box design) to let people know this is a different experience will go a long way toward swaying potential Wii customers from walking out of the store without a Wii and instead, with Natal.
How they handle this launch will be crucial in it's success.
Even simple integration modification of games in progress right now would go a long way. Mass Effect 2 would be a good example. Code an optional Natal interface where the gamer doesn't have to walk the character through all the details. Controlling the game more like an interactive movie by speaking or even selecting responses and pointing at destinations and threats to be dealt with.
Many gamers wouldn't find it interesting or involved, but Wii type gamers would see it as something not capable on that platform and compelling as an alternative game type.
The potential is huge ... I hope it isn't wasted.