While extended diagram definitions may be helpful for some situations (such as the Database diagram example), it seems to me that more flexibility in the existing template mechanism may be sufficient for many uses.
I mentioned one such use in my other post (
[size=13]Idea: Show Diagram Stereotype in Project Browser[/size])
As we define classes of diagrams, it would be extremely useful to have a template for each class of (say) component diagrams used in the Architecure.
From an outside point of view, it would seem that adding a stereotype combo to the New Diagram dialog would be a simple matter (given stereotype is a property of all diagrams). From that point, it should be simple to select the particular template to use when creating a new diagram by matching the stereotype.
If this is as small an effort as it seems from an outsider's point of view, it would be really handy while we wait for a more sophisticated solution.
Comments?
ps. I've noticed that diagram notes and text elements don't seem to be copied from the template. Getting a consistent base diagram including things like Diagram Notes would seem to be a typical use for a template. The properties seem to come over OK though.