The Augmented Reality view gives you the size information that you don't have in a browser. If you look at the Apple I for instance in AR you can do this kind of comparison : http://augmentedev.com/files/AugmentPic26.jpg
Or your overpowered iPad. But yes it's basically it. Except that you have more information by doing this since it gives you the size of the object (useful for la Joconde and Apple I for exemple). And you can compare several objects together. Two things that you don't easily have with an embedded 3d browser.
The printing part is a problem that will resolve by itself when the technology evolve. But yeah, right now it's the main point of friction. Even if you can display the marker on your screen and look at it through your tablet. Or display it on your tablet and look at it through your phone.
I still don't really understand to process to get new stuff in wikipedia, it seems really complicated to change something there. I guess when you have so many content you need to have some inertia but still.