I've been working a lot on setting up the service catalog, and I've run into an fairly arduous process here. I have to have a Dispatch'r rule for almost every item in my service catalog to properly classify it with the right type, category, priority, and assigned group.
Wouldn't it make more sense to display the fields from the ticket field template and allow me to define the defaults that should be automatically entered when this service is requested? Since the user doesn't ever see those fields, they can't fill them out and a bunch of stuff comes in blank and has to be manually classified.
This would leave me with just having to deal with assigning it to the appropriate group, and that can be addressed by simply adding the service catalog category to Dispatch'r rule parameters (this is on a separate feature request)