As SM said, I'm thinking that Cameron wasn't impressed with the lack of Shaw's inclusion in COVENANT, apart from seeing a photo and a mutilated dead body. That certainly would have brought back memories of how his Hicks and Newt characters were handled in ALIEN 3!
Just seeing even a little bit more of Shaw's inclusion in this PROMETHEUS follow-up would have been welcome, before we came to the eventual reveal of her demise...and I think it was a missed opportunity that Ridlley didn't include Shaw's originally intended footage. Thankfully, the moments of Shaw in the 'Crossing Prologue' footage will be available for myself and others to incorporate into our own edits of the movie...and this will help to make up for her lack of involvement overall - as well as showing how she went about restoring David back together in the first place.
It's not much, but I reckon that some of that footage will help to ease her character's minimal inclusion somewhat.