Currently when you are writing an ability at the bottom is a very helpful section that tells you how to reference attributes or macros, but unfortunately it says nothing about referencing other character abilities. The problem is that unless someone already knows about this feature they assume incorrectly that it is impossible to nest character abilities. I would love to see it change from Use @ to insert Attributes, # for macros. to Use @ to insert Attributes, # for macros, and % for abilities.