Great, my first thought was up and down arrow, but people may expect that the four arrows (up, down, left and right) will move the picture. The + and - on the numeric keypad work for me, but not for those with a laptop that doesn't have a numeric keypad. Perhaps changing the angle could also be done by the angle brackets "<" and ">" (and also the unshifted versions, "," and ".") ? But keys either limit you to a large angle, or require you to hit them many times.
A control like powerpoint has would be good (a handle outside the image that you grab and use to rotate the image). Also, can the images be resized manually?
How about a "spot weld" mode in the first window (top one), where you can move two pictures over one another then pick a spot to put CPs in that location for both pictures?
It would save a lot of trips to the other window! Aligned with that idea, perhaps CPs could be visible in the first window with one pixel per point?
The earlier discussion about an easy version of Autopano and a professional version of Autopano could be answered with "both!" - the first window is the easy one, the second window is the professional one.