While I understand the advantage that it would reduce the number of
config files, I do not think it would be a good idea to put Seam related
config XML elements into standard JEE config files such as web.xml. Why?
Because then users would no longer be able to validate these config
files using an XML schema.
You can still validate an XML file against XML schema as long as the schema has an <xs:any/> element. This element tells the schema to worry about it's own nodes and ignore any it doesn't recognize because they are in a different namespace. This is the whole idea of XML.
-Dan