Ok, generative fill still have a lot of flaws but as a first iteration it is quite impressive. However, I think one of the most important things to improve is "consistency".
For example: in an album with multiple photos of the same subject in the same scene, I'd like to add "angel wings" to the human subject, and I can get a pretty good looking wings that doesn't that doesn't look too "off", however, the problem is that it is pretty hard to get the exact same type of wings to add to the same subject in a different photo of the same album because when I use generative fill to add wing to the subject, and different wings is created.
Excuse if my explaination is a bit hard to understand, English is not my first language.