For anyone who happens across this thread, the topic was touched on in two other discussions.
Mid-December 2013, the Photosynth team brought this up as a solution in this thread on clarifying where a synth fell apart: http://bit.ly/psflusp and asked,
"Question for the old-timers -- those who used the original Photosynth and tried to get things that were 100% synthy, or close to it: Did the 2D view help? In particular the fact that we laid the 2D view out in "connected components", showing the biggest one first? I'm considering bringing this idea back -- with the difference that in the new Photosynth only the biggest connected component would actually be visible in 3D -- the other photos would be there as thumbs, and you would have to look at the breaks between the sets to work out where you needed to add shots. Would that help?"