You do see God wants to outlaw slavery as was practiced in the South, correct?Sure, but the best laid plans of mice and men, and all that.
I think one can say that Paul requires slave owners to care for their slaves (which is smart, economically; even when Nathan Bedford Forrest, the man that General Grant feared with all his heart, before Forrest was a Christian he was a fair and decent slave-master. He never broke up families--largely because that would make for bad conditions on the farm).
And I think Christian wisdom does intend for the gradual emancipation. But here is the problem: the Bible never really says that, unless we want to go theonomist and say Leviticus 25 applies today.