As an Atlas map user both embedded in syndesis or standalone,
A. I would like to be able to map nested collections. (Not related to Expression Mapping)
B. I would like to be able to map partial collections. (Many to Many)
C. I would like to map a collection from any level in my source to any level in my target. (Example Required)
D. I want to be able to map one collection to another. (Many to Many)
E. I want to be able to map source collection field.
A and E can be considered "just" enhancements (and depend https://github.com/atlasmap/atlasmap/issues/890)
B,C,D are indipendent advanced features.