Related to other topics about viewing. I feel the browser is no longer the preferred way to go, but apps are. Therefore, I feel you should definitely have the standard Windows (Phone) 8 Photo app hook into the Photosynth library soon. I would say, have a crash team on it to be ready when you move the new Photosynth to general availability.
Moreover, synthing should begin in the Photo app, comparable to what we now have with Photo Gallery. Select the photo set in the Photo app and then share to the Photosynth app with the share charm to assess, upload and monitor the synthing process.