Controversy over Second-Tier Doctrines?

Should controversy and debate ever occur over second-tier doctrines in the church? John Piper makes an excellent case for the importance of preserving secondary doctrines:

“For the sake of unity and peace, therefore, Paul labors to set the churches straight on numerous issues—including quite a few that do not in themselves involve heresy. He does not exclude controversy from his pastoral writing. And he does not limit his engagement in contro­versy to first-order doctrines, where heresy threatens. He is like a par­ent to his churches. Parents do not correct and discipline their children only for felonies. Good parents long for their children to grow up into all the kindness and courtesy of mature adulthood. And since the fabric of truth is seamless, Paul knows that letting minor strands continue to unravel can eventually rend the whole garment.” (p. 31, The Future of Justification)