I recently upgraded to iOS 7 and found that I could no longer straighten and rotate.. I have been in communication with Nik/Google support. The issue comes down to aspect ratio. I posted a quick youtube video on what is happening when I try to straighten / rotate an image with the aspect ratio of 4:3.
http://digitalchemicals.blogspot.com/2013/09/snapseed-bug-w-ios7-43-aspect-ratio.html
http://digitalchemicals.blogspot.com/2013/09/snapseed-bug-w-ios7-43-aspect-ratio.html