Assuming this rumor proves true:
Has anyone else thought that perhaps, just perhaps, the reason Apple would want to make this the new AppleTV remote is because they want to ensure that AppleTV owners can control apps should Apple get their heads out of their butts and open up an AppleTV SDK and App Store section, as they did for iPhone/touch? Remember, iPhone/touch didn't really take off as a platform until the SDK was released and the App Store opened.
Why would such a remote be needed if "most AppleTV owners have an iPhone or iPod touch"? Well...because that's a silly assumption, first off, and there's no way to really ensure it at all. For all anyone knows there could be quite a larger portion of the AppleTV userbase that own "classic" iPods and NOT the lower capacity iPhone or iPod touch.
That said, even selling this as a peripheral, an add on, doesn't ensure most AppleTV owners will get it. So...I think Apple will release a new AppleTV, a "next gen" device with this new touchscreen (and hopefully accelerometer enabled) remote bundled together. Current AppleTV owners would have to upgrade to the new gen device to use the remote and gain access to the new AppleTV App Store.
Apple would then extend the function of the AppleTV the same way they did with iPhone/touch.
For instance, Hulu is apparently working on an iPhone/touch app. With an AppleTV open SDK and App Store, theoretically Hulu can release a Hulu app for use on AppleTV. The streams would likely be limited to SD content, but as the current Hulu has a little pop up every now and then on their site to "buy it in HD on Amazon" that little pop up would be replaced with "buy it on HD on iTunes" and it would be sort of "free" advertising for iTunes tv show downloads.
Also, productivity, creative, etc. apps could be developed, further extending the usefulness of AppleTV over other media set top boxes. Sure, Vudu can show full 1080p24 and has a larger library, but can you quickly edit photos on it, or check a spreadsheet, or download and upload a youtube vid quick and easy? Oh, you can't. Well, you could on this hypothetical extended AppleTV with the new App Store and new "do just about anything" touchscreen and accelerometer remote because, well...there'll be an app for that.
And, lest we forget...GAMES. Games are the major sellers on the iPhone/touch as far as best individual app types are concerned, and so too would they further extend the userbase of this new AppleTV. Game companies were interested in Apple opening up an SDK for AppleTV, and if this new remote extended the capabilities of the current device, or were bundled in with a next gen upgrade, then devs need not worry about control interface. They'd basically spec up from iPhone/touch development.
The included accelerometer wouldn't be different from what Nintendo has with the Wiimote, or Sony and MS are planning with their eyetoy wand and Natal, respectively. Hell, Apple could even bundle in a camera system ala Natal, therefore ensuring a better userbase for such a camera controller-less control system. But even if they just have this new remote, it would be different enough from Nintendo, MS and Sony's offerings because of the multitouch screen alone. Nintendo thought that DS, with a pen would open up gaming to new consumers because everyone knows how to hold a pen. Well, Apple wouldn't be that far off because everyone knows how to swipe a surface.
It'd be like the Wii but for grown ups.
Added benefit is that it wouldn't compete directly with any of those, as it would basically be an extended media device, not simply solely dedicated to games, just as is the case with iPhone/touch.
Of course, this rumor could just be complete bunk...but it makes more sense for Apple to bundle in such a new iPhone/touch-esque remote than assume that AppleTV owners already own an iPhone/touch or that prospective owners would go out and buy the iPhone/touch to use the extended capabilities of the new AppleTV.