Church of Christ doctrine is a meadow of sacred untouchable cows. They have not always been that way. The churches of Christ have been willing to adjust their thinking on numerous "doctrines" throughout its short history.
1. The Churches of Christ were once universally tolerant of slavery. Churches appointed elders who were slave owners. Many preachers unabashedly advocated for the institution of slavery—race-based slavery! Today, most Christians believe it is a sin to own another person. The case for slavery is easy to make. It depends on a plain reading of scripture. Abolitionism is a difficult case to make. It requires a careful reading of scripture with a non-hermeneutical emphasis on God's character.
2. Amillennialism. The churches were almost universally premillennialist until the recent preaching of Foy Wallace and Jim McGuiggan. Those two change-agents moved the whole body of churches of Christ away from premillennialism.
3. Women's vote: The churches of Christ were universally against women voting on politics on the basis that (a) the man is the head of the household and (b) women are more easily deceived than men—as evidenced by Eve"s deception and Paul's mention of Eve's deception in several places. The church resisted the women's vote for decades after the right for the women's vote became law. The church slowly changed its view when it became abundantly clear that women are no more or less deceivable than men. Women are also equally able to excel academically as men. (An argument against the women's vote was that women were not able to achieve the level of academics that men can).
The church has changed majorly in other non-doctrinal ways.
