What if Wesleyan denominations didn't exactly merge but formed (as Devin Rose put it) a kind of "UN of Wesleyan denominations"? Then the more it worked, the less the current denominations would need to function until eventually, in effect, we had a new uber-Wesleyan connection.
Here are some things I've heard as suggestions or brainstormed myself:
1. What if it was something that individual Wesleyan, Nazarene, FM, etc. local churches joined as the real "atoms," with the denominations themselves only setting it up and providing initial leaders? Maybe something like the Willow Creek Association?
2. What if this uber-connection provided services to these local churches like pension, health care, insurance, etc. so that the individual denominations no longer needed to fund these things?
3. What if those churches who joined were excused from a certain amount of denominational "tax," such as that for educational institutions? What if those educational institutions that could support themselves became more associated with the connection than with their current denominations?
4. What if, as soon as the connection reached a critical mass, these local churches elected a council of leaders from regions and/or some other groupings?