AI tools are now common in Lightroom, such as Masking and Healing - what if there was a feature available in the crop and rotate menu that allowed the crop region to expand outside the boundaries of the original photos frame, and the blank areas are then filled in with a Healing AI. See image below.
This could give photographers more flexibility in framing images, especially if the subject takes up majority of th original frame. It would obviously only work well on low detail areas such as sky or foreground.