My conclusions were affirmed (at least to me) when—after the paper was done and presented—I picked up Scot McKnight’s new commentary on Paul’s Letter to Philemon. His own thesis and conclusion offered a similar framework as I regarding what Paul was seeking to accomplish in his Letter to Philemon.
From McKnight’s commentary regarding Onesimus, Philemon, and Paul . . .
“Was this purely a spiritual equality . . . That is, [Paul’s] vision was not for the mansumission of slaves in the Roman Empire. Rather his view was about something other than legal manumission, that is, a new creation sibling-based fellowship on the basis of adoption as children of God. For Paul this was a nobler vision and one (for him) more penetrating. For Paul the social revolution was to occur in the church, in the body of Christ, at the local level, and in the Christian house church and household.
“. . . Paul sets a tone for leadership that counters typical Roman ways. That is, to use the language of Victor Turning, Paul formed some anti-structures to the structures of the world, new anti-structures shaped by personhood and community or fellowship, with the ekklēsia being the location. In the anti-structure, Onesimus [the runaway slave turned Christian] is no longer a slave but a brother, and Paul (not Philemon) is the father, and Philemon is a brother to Onesimus . . . Paul’s concentration was the faith-community and fellowship not the Roman Empire and its structures . . . Revolution occurs in the new relations shaped by love in the oikonomia of [household] of Philemon in Colossae not with swords and shouts in the Roman forum. Paul did not so much turn a blind eye to the morality of slavery as he did not realize slavery was an issue of morality. He was blind to the immorality of slavery as an institution” (pp. 10-11).