I think the Model-based Tracking link showcase’s a good path forward, particularly if data is collected on mass to create such models (or at least, key-points) Microsofts Photosyth technology could well lead to a very large collection of landmarks around the earth automaticaly modeled in 3d from photos.

full angle sensing is now a low cheaper thanks to Nintendo pushing down the prices. (or at least, will be, when the millions or so orders of the small gyros needed for the wiimote upgrade go though).

And better GPS will be coming as soon as europe gets its act together with Gallio (accurate down to the meter for cilivian use).

Its only the output devices that are really lagging behind, imho.
Companys are still scared to go near anything remotely like VR headsets, even optical see-though or eye projection. (both very possible with todays technologys if they were invested into).

At the moment AR is either where a massive bulky custom headset (video-see-though), or lose the use of your arms.