This is such an important and difficult question. I’d recommend, for starters, you read “Recovering the Scandal of the Cross” (by Baker and Green). There will be a sequel to this book in the next year or so, and I’ve contributed a chapter to it.
Short answer: I think the gospel is a many faceted diamond, and atonement is only one facet, and legal models of atonement (which predominate in western Christianity) are only one small portion of that one facet.
Dallas Willard also addresses this issue in “The Divine Conspiracy.” Atonement-centered understandings of the gospel, he says, create vampire Christians who want Jesus for his blood and little else. He calls us to move beyond a “gospel of sin management” – to the gospel of the kingdom of God. So, rather than focusing on an alternative theory of atonement, I’d suggest we ponder the meaning and mission of the kingdom of God.