I have found that in the autocephalous Catholic world the bond that is stronger than anything else is friendship. It overrides so-called "communion agreements," distance, liturgics, even sometimes complex (but not generally not basic) doctrine. I think there is a good reason--because we all want to connect with each other on a human level. We want to find others out there, like us, who want to belong. A close friend was recently consecrated a bishop, and I wish I could have attended but travel plans prevented my attendance. The event brought together people of differing views and even some whose official policy is cautious towards interjurisdictional participation. It happened because of common friendship and care for the consecrated, who is an exceptional person.
The modern ecumenical movement hinged on the 1925 Wold Conference of Life and Work in Stockholm, Sweden. During this event, members of churches from around the world (with the exception of Roman Catholics) came together. They shared stories, experiences, and wisdom. Events such as these often serve as a springboard for further efforts to work together, because people simply get to know each other.
It can be common in the movement to attempt replicate the model of larger churches. That is, to say "we're different so we will have nothing do with them." This can be done out of fear, out of the desire to maintain purity, out of a sense of control, out of concern of being affected by a negative image, and out of many other reasons (both good and bad). But, I have found that as people get to know each other organically these arguments often fall apart. Relationships form and people come together--just as is happening with mainstream Christianity in the USA.
What this means for the larger movement, I don't quite know. As I said, there can be legitimate reasons to be wary of a person or group. This largely because the movement does not have the resources of institutional churches, so cannot control for clergy who may be ordained where they really should not have been in the first place. I think we need to control for people who can be emotionally and spiritually damaging. But, I think we have to realize on some level that our attempt at building walls will see them crumble when people meet, speak, and share a meal.