A Content's model could have attributes, handled by a DataHolder, but also read-only properties so that a call to content.getValue(name) :
1. First check if there is an attribute named "name" in the model
2. Then check if there's a system property named "name"
3. Then check if there's a property named "name" locally

Properties should be available as view items, may be SAXed, ...

Special properties could actually be functions, such as count(repeater)

Special attention should be taken to views created from the model, to views used for editing, ...