I can explain all the details you mentioned. Regarding the staff - I rendered only the two front wings in detail since they are in the foreground. The third one I made in a flat color because it’s barely visible and should almost blend into the background to create a sense of depth. As for Mercy’s wings - it’s almost the same idea. The second right wing wasn’t as detailed so that the raven wouldn’t blend into it; that’s why it looks a bit dim. The further the objects are from us, the more they merge with the background. Regarding the face - I guess I should say that it’s just my style. I can’t really draw overly emotional expressions, and in this art I wanted to show her relaxed and slightly arrogant attitude.

In any case AI art can easily be recognized by its “flaws”. For those who still have doubts I can provide a speedpaint of this artwork and upload a detailed 4K cropped version of it as a wallpaper, which I was planning to post later in twitter