I like the idea of curation reports. Curators should specify why a post is worthy of a high vote, otherwise it is unclear if they read or checked the post in detail. Such reports also create implicitely a clearer image of the Steemstem voting standards.
As steemstem is in sense paying for good posts, there should be some kind of receipt. A curation report makes sense in this context since it directly links the post-vote to a curator.