I got an email from Paul this morning making some comments on my post. Paul said that he always creates a database from scratch. He said that this gives him a warm fuzzy feeling as he then knows that the installed binaries and patches are in good shape. He follows, that he knows he doesn't need to re-patch or run catpatch.sql and also it puts the hardware through its paces. He also said he is not against cloning in general but he just doesn't start on a new database server.
I liked the title of Paulís email to me "catpatch and rm -rf /opt/oracle/product/10.1.0/db_1/assistants/dbca/templates/*.dfb" - It is good advice to delete the templates for many reasons that include space or security of the files as they can contain sensitive data.
Thanks for the email Paul and the good insights.