Well, a mouse doesn't know its absolute place on a 2D surface either. For that, you need something like a Summa tablet and pen. I don't see this as a problem at all.
Edit: I'm definitely with you on the gesturing for the novelty of it instead of only when it makes good sense. Like with the fucking microphone on the DS, Nintendo needs to quit advertising their console gadgets by strong-arming their devs into using them when a button press or joypad move would do the job better.
For the first part, yeah I don't really know. I'm just going off of what others are saying, and I'm assuming they know a lot more about this kind of thing. I think it's that you can't actually have 1:1 movement like people think of without having at least one other (separate) item that's not the sensor bar or the wiimote so that the sensor can use to calculate wiimote positioning. Like a little pylon that could very well be stationary the whole time, but the machine needs it there in order 'backsight' it to calculate the position of the remote in relation to it. Ideally, you'd have two other sensors. I may be looking at this wrong, but at least that's how all three dimensional positioning algorithms work with things like Total Stations and GPS surveying equipment.
And the edit is what I see as the main flaw with the Wii. Like I said, I had one (or a roomate did) and it was great, untilI caught on that almost every game that wasn't wii sports was just tedious. That was close to launch, but apart from a few gems, I don't think much has changed.