I can't believe I had forgotten to include this as an idea, yet another customer just reminded me:

Templates are a great time and confusion saver for technicians, but I'd think it's obvious that  they're even more useful for users, who do not necessarily know what is the right combination of Type-Subtype-Category for any given request - nor do they really care.

If templates were available for users on the Self-Service interface, we could hide the Type, Subtype, Category and Priority fields, and  it would be a simple matter form them to choose templates that sound meaningful to them: e.g. "Printer Out of Toner", "Mail not Working", "No Internet Access", "Word Hates Me", or whatever  makes sense, instead of such obscure choices as: Service Operations-> Software Services-> Diagnostics,   or whatever combination IT has devised.