One of the things that can change in the program is -> because when creating a bone and setting a picture to hold, you must first select which bone to hold the newly created, in my opinion this is an additional delay.
In my opinion, the right way is if there is no selected bone to attach the newly created bone, the program will automatically create a bone to the root and add the image to it.
The other thing is the ruler, which is added, there is no possibility to draw lines.
There is no hotkey that automatically puts key-frames on all (rotate / scale / move).
Missing key, as in photoshop when you scale an object (Maintain aspect ratio) if you pressed the padlock, proportionally scale and (x, y) the only way at the moment is to use axis in viewport.