This is a tricky issue. Some people would prefer to export everything (so the import process from their side is easier) and other people will prefer to avoid exporting linked/duplicated cels/frames.
For example, in this case:
Aseprite exports:
body1.png
body2.png
body3.png
body4.png
body5.png
But with this new behavior should export:
body1.png
body2.png
body5.png
The bad side is that Aseprite then cannot reload this kind of exported sequences (but it might not be a problem for you).
Maybe a new --ignore-duplicates
option would be enough.