OK, I don't like the lay/clergy distinction but recognize it is there. However, there is a long history within the evangelical tradition of theologians in the pews, not simply in the pulpit. In fact, it was the theologians in the pews who left the state church in Europe and formed "free churches" when the theologians in the pulpits no longer held to the truth of the Scriptures. This illustrates the importance of ordinary men and women who are also biblically literate. We cannot simply outsource the role of theologian to those with the requisite degrees. We need people who think deeply on the things of Scripture and their application to life and the church.
Perhaps the Bereans of the New Testament best illustrated this tradition as they carefully studied the scriptures. Today, every tool available to pastors is also available to the rest of us - even tools to study the original languages (without having to learn them and most pastors forget what they learned of those quickly and use those tools as well).
There are many believers who are content with a simple knowledge of God and Scripture. But the health of the church requires that there are also those who go deep, drinking regularly at the well of truth and are able to teach and translate that truth to the lives of everyday people. It is a laudable goal, especially if that learning first goes into the lives of the learner.
When I was a child it was not unusual to have such people fill the pulpit from time to time. Today that is rare but there are more people who can teach and preach than we often acknowledge. It makes a statement when someone without a seminary or Bible school degree gives the message. It illustrates to others that Biblical truth is accessible to all rather than some.
It is often those "lay theologians" who challenge the church in missional directions. They are less enamored with "scripture light" that characterizes much of today's preaching. That is why effective Bible teachers in the local church are so loved. Many want to delve more fully than Sunday mornings lend themselves to.
If you are a lay theologian, a theologian in the pew, I salute you. You are deeply needed by the body. Keep it up and help all of us both love the Word more deeply and apply it more effectively. If you are a pastor, what are you doing to encourage, use and build into the skills of your theologians in the pew?