This idea has been wandering my mind for a long time
Glad to see it being discussed. I want to add my 2 cents:
* MODX is now template-centric, while it should be resource-centric. Resource Types would achieve that, and templates are just that -- a way to display (provide) the content to user. Template is about presentation, resource type is about structure.
* Resource types extend the core resource type, which ’contains’ only minimal metadata like id, dates, authors (no titles, aliases, descriptions, content etc.).
* Resource type has its own set of fields (elements), which can be defined the way TVs are.
* Resource type has templates attached to it exclusively with content types and disposition.
* Resource type defines how it displays in manager -- in tree or in grid.
* Resource type is defined inside manager UI.