I think that we universalists somehow realize that proving that the Bible teaches the doctrine of universal reconciliation gets us only so far. The problem is that Catholics and most Protestants (I don't know about the Orthodox churches) put the authority of the church above the Bible. What we need is a deeper understanding of the authority of the church and how it relates to the Bible. We all agree that the Apostles including Paul had authority to interpret the Bible for the Christian believers as well as for enquiring non-believers. The question is was this authority passed on to the the church leaders who succeeded them? If this authority was passed on to subsequent generations of church leaders are we obliged to obey them? And who are they? Do they even exist?
My older sister, a staunch Catholic, told me that anyone can make the Bible say anything he wants it to say. Therefore one must submit to the teaching of the church, the only sure guide in the interpretation of the Bible. She has a point. On the other hand the history of the Christian church in its many manifestations does not give many of us confidence in its legitimacy.
The Protestant Reformation succeeded to some extent because the reformers were able to delegitimize the Roman Catholic Church in the eyes of millions of believers. But I'm not sure which came first. Did the reformers delegitimize the church by proving through the Bible the doctrine of salvation by grace alone and other reformed doctrines or did they delegitimize the church first by pointing out the corruption in the church etc., etc. and then the people were prepared to accept new doctrines?
My own feeling, and I'm not dogmatic about this, is that the house church is the only legitimate form of church. The big denominations with their large congregations is what is really standing in the way of conversion to real Christianity, to a universal belief in universal reconciliation. One way of bringing these leviathans down is to break the power of their money to keep pastors etc. in line. As long as pastors, priests and other church authorities depend on income from the church for their living, these shepherds of the flock are not going to jeopardize their "job" by entertaining controversial beliefs like universalism. The church should never have gone the route of full time paid clergy. One possible solution would be to organize sympathetic employers into an association that would put priority on hiring ministers, pastors, priests etc. who lose their clerical jobs due to their rejection of church doctrine such as the doctrine of eternal damnation for the lost. (Unfortunately the job situation is not good in this or other countries. And I don't have a clue how to go about organizing employers for something they probably would have no interest in.) This is a vicious cycle. Ministers, priests, pastors and bishops are not going to move unless their church does but the church won't change unless its ministers, priests etc. change. The beliefs of millions of Christians are tied into this immovable church system and it doesn't look like proving this or that from the Bible is going to break this logjam.
That the Catholic Church recognized this power of the purse to keep its priests in line is evident in its getting the government of Mussolini to agree to pass laws prohibiting Italian corporations and other businesses from hiring ex-priests. And when I was arguing for the teaching of universal salvation with a pastor (Reformed Church) I had after leaving the Catholic Church, I realized that until we addressed the issue of his financial security this pastor was not free to really consider my arguments from the Bible regarding universal reconciliation.
Just some thoughts....