Schism is a kind of heresy, to be sure. The question we will all have to figure out will be: "Who caused the schism; who committed the heresy?"
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This is no easy question.
We have so many interpretations (and translations) of the Bible that it would be inaccurate to claim that the Bible unites us. If someone believes, for example, that interpreting Genesis 1 literally is the only legitimate approach to that text, they can hardly be united with someone who approaches it more allegorically.
It would also be inaccurate to claim that we are united by our doctrinal standards. It's extremely rare for anyone during our Annual Conference session to make a reference to our Articles of Religion, for example. John Wesley's sermons may see an occasional reference, but much of this seems historical or, at best, inspirational for many of us. I have been with pastors who have denied one or more of our Articles; it isn't pretty.
While United Methodist clergy do function within the lines of apostolic succession, I don't think that this is what unites us. Most United Methodists aren't aware of the succession and could likely not care less.
Clearly, we are not united by a common liturgy, such as that which unites the Anglican Communion (at least in part). While I have my own preferences ("smells and bells!"), I think the diversity of our worship can be a good thing...from High Church to Southern Gospel to Baby Boomer to Emergent, and everything in between. It can be exciting and all very faithful when planned well theologically, but our liturgy clearly doesn't unite us.
We are not united by a common law or Discipline; for this, I blame primarily the left wing of the Church. They tried to find loopholes in Church law...just as the world would do...in an attempt to salvage the ordained ministry of someone who had admitted to being in violation of the law. In doing so, they played politics with the Discipline, and disregarded the clear wish and intention of the General Conference and our covenant together. That was very dishonest, and demonstrates to me that we are not united by canon law (remember - the issue wasn't sex...it was whether or not Church law had been violated).
Our common history doesn't really unite us, especially as we take in more and more folks who are former Roman Catholics or former Presbyterians or former Pentecostals or former atheists, agnostics or pagans. We may know about the history, but are hardly united by it.
It would be wonderful if we were united by a common mission, but, frankly, we can't seem to agree as to what being a disciple means, much less how to make disciples. And with the theological error of adding "for the transformation of the world" to our denominational mission statement, we are less united by mission than ever before.
I'd

And maybe that lies at the heart of our problem. Our problem isn't primarily ethical, and it's not primarily Biblical. Our problem is primarily Christological. We simply don't know what to say about or do with this Jesus fellow.
The Right Reverend Eric Park wrote in his summary for candidacy as a General Conference delegate, "I am convinced that [one] of the most significant challenges facing United Methodism [is]...daring to live a life that is subordinated to the Lordship of Jesus and the countercultural ethics of the Kingdom of God."
That's it in a nutshell: how do we live a life that is subordinated to the Lordship of Jesus? We have no common understanding of what that means, especially as it relates to Holy Scripture, the Great Tradition, Reason, and Personal Experience.
Perhaps, before we have another General Conference, before we discuss any changes in Church law, we ought to find some common ground concerning the person and Lordship of this man Jesus Christ.