If you want to get married legally, get married legally.
If you want the blessing of your church, then get the blessing of your church.
But I think it's a very LOUSY idea to have the pastor act as a legal liaison because it contributes to confusion about who has jurisdiction where and whose marriage it is.
If that distinction is important to people, we should be able to come up with some basic way to implement it. So is that really the issue? (You seem to be responding to implementation questions.)
If the distinction is not important, we're going to have LOTS and LOTS of arguments culturally about this until it's figured out somehow and the distinction gets made.
Gatsby, you're right; I'm still arguing on a broad conceptual level so I wasn't delving too far into the flaws of using statistics. I also think it's a great idea to suggest a look at how things have played out elsewhere, even if cultural differences might have to be factored into things.