When I worked for an outsourcing firm we were constantly asking firms what their "core functions" were, or what were they in business to do. Any other function they performed was important, but not a key component of their business. These non-core functions could likely be outsourced to a specialist while they freed up time and resources to devote to their core-function.
In looking at Church, the question becomes what are the core functions? Once those are defined, everything else is a potential for outsourcing to either a para-church or secular "specialist."
Hundreds of bible passages speak to the purpose of Christ's church, and although they often go by different names, five main themes emerge:
(Roy King - What is a healthy church?)