If you want to combine your work with Ubuntu, you can for example look at the GIMP bugs in Ubuntu's bugtracker.
I sometimes compile versions from source into my system to test the bugs I have reported, if they are fixed on my system. On the other hand I like testing new features in early stage of development.
I'm not a GIMP developer, but I am a member of the Ubuntu Bugsquad team.
Just curious what you mean by "automatic reframing"? When you crop an image to pick out a portion of it, how would any program know what part of the image you wanted (or how far to rotate it which way)? If you want certain pixel dimensions for a crop in gimp you can always drag a horizontal or vertical edge (dimensions show at the bottom) or move the area to be cropped once you drag the edges to a particular size. Image > Scale Image can resize either the original image or whatever you have cropped. If I want to crop something that does not end up at the dimensions I want, I do the math so horizontal and vertical ratio will then scale to the size I want to end up at.
In gimp if you crop and rotate separately, you can always Edit > Undo multiple times before you save it, or File > Revert to completely reload the original image and start over.
Here is how you can do what you need (crop+rotate image) in GIMP:
1. Open the image.
2. Select Rotate tool, and then in the Rotate options panel, make sure Clipping is set to "Crop with aspect", and then go ahead and rotate the image the way you want.
3. After the image is rotated, go to Image > Autocrop Image.