What do people think about taking the "markable" types out of the coreference project and adding them to the standard type system? This is a pretty standard concept in coreference that doesn't really have a great natural representation in the current type system -- it encompasses IdentifiedAnnotations as well as pronouns ("It", "him", "her") and some determiners ("this").
The drawback I can see is that it is probably not something anyone would want extracted -- ultimately you want the actual coref pairs or chains. But it is useful for things like representing gold standard input or splitting coreference resolution into separate markable recognition and relation classification steps. Tim