The big winner will be an easy 3d modeler.
Oh, I agree 100%. I was thinking a phone could be ideal here. You'd just wave it through the air, drawing what you want, you could review what you've drawn in the screen and adjust parameters, and it could vibrate to give haptic feedback to help you draw in a straight line, or let you know when your path connects to another that you've drawn. Stuff like that.
Unfortunately, it looks like there's too much noise in the accelerometers to make the double integration to position meaningful. Something like Sensor Fusion[1] can make it more accurate by incorporating data from the gyroscope and compass, but even so it's not enough.
In any case, like you I hope someone develops something intuitive to really help 3D printing take off. The future should be interesting...
Making general models by waving a phone around would be difficult enough, I can't imagine trying to use it to create a model detailed enough to actually print a usable part.
Now, making 3D modellers is actually something I have a lot of experience with. If anyone wants to have a discussion about how we could actually create an interface for a 3D modeller targeted at consumer modelling of 3D printable parts; Well, that's a discussion I'd love to have.
I guess, it's easy for me to imagine a shape - i can draw that shape on a piece of paper, but i find it hard to express that same shape using modeling software.
Say, wrap some text around the surface of a sphere. I'm pretty sure i could, letter by letter, orient and kern text in OpenSCAD but it would take me a long time to do.
i imagine in the not to distant future there will be a motion tracker or kinect app to allow shaping stuff like clay - or maybe just use clay and scan it in.
In any case, all the software i've used feels clunky. iMovie for modeling will be a big deal.