Total Ministry is a huge concept that is hard to get our arms around all at once. This is okay, because the only one who needs to get their arms around it is God. Once we are safely in His arms we can strike out into the huge idea and not flounder.
Total Ministry is often seen as a "Small Congregation" process or program. It is, but it is also good for larger congregations. Small congregations (70 worshippers on Sunday or less) are often motivated by economics and a desire to keep their doors open. Larger congregations are also feeling an economic crunch. In an effort to pay clergy a competitive wage we have priced ourselves out of the market. We have buildings that are moldering. Is our job, as a church, to pay the clergy and keep the buildings standing? It is not. Total Ministry is a new ecclesiology and a new praxis that addresses the job of the church.
The Total Ministry idea of community is very important. We are a biblically-based community, but we are also human. For example, some one comes up with a bright idea. How does it get implemented? The community has to see whether or not they want that idea in that time and place. 1 Corinthians 13 plays a huge role here. People need loving and caring both on the side of the individual with the idea (so she/he won't feel rejected) and the community (so they won't feel pressured to do something they don't want.) The community is where we get our needs met and is also where we corporately meet God.
The 1979 Book of Common Prayer places huge emphasis on weekly Eucharist and the Baptismal Covenant. Total Ministry helps all sizes of congregation fulfill these emphases and does so without money for implementation. It frees up everyone to do their baptismal ministry, including the full-time priest in larger congregations. There is a desire to do more ministries, both inside the congregation and outside. Total Ministry gives people the tools to be able to do this.
These are just some reasons why congregations and their diocese should get into Total Ministry. You will find others as you work through the process and understand scripture more and more when seen through the lens of Total Ministry. Remember, the only one who has to get their arms around the whole thing is God. I think God is big enough for the job.