I think one major point is security or more precise: to detect possible problems early on. If you now use a wrong type information, which means address a component that doesn't exist, you get an exception immediately on startup. So, you know very early that your application is not correct.
With a dynamic type attribute you defer this to a much later point which might be dangerous as well and very hard to find.
Moreover, the use case shows a component type coming directly for the request URI, which is a giant door open to "component injection" by providing a value for the type that is not in the expected values and executes arbitrary code on the server.
Sylvain
-- Sylvain Wallez Anyware Technologies http://www.apache.org/~sylvain http://www.anyware-tech.com { XML, Java, Cocoon, OpenSource }*{ Training, Consulting, Projects } Orixo, the opensource XML business alliance - http://www.orixo.com
