Doctrine: a rationale?

Why do we need to do doctrine? What does it add, except for confusion?
In my personal experience Doctrine, or Theology, as a subject has had rather a bad rap in evangelical circles. Few people at college put it as their favourite subject (though I could be wrong); and the majority of time we spend in study is usually allocated to Biblical Studies; we rarely preach on doctrinal issues. There is an understandable reluctance to move what seems to be one step away from the clear text of the Bible itself.
Why is this the case? I have three suggestions:

§ The problem of systems
We may rightly be wary of letting a constructed theological system or tradition override the text. We have all seen Biblical texts squeezed out of shape in order to make them fit a theological presupposition. Roman Catholic dogmas about Mary’s perpetual virginity are one example we may cite, where the most likely meaning of the gospels is that Jesus had brothers; yet the Roman Catholic system, with a prior commitment to Mary’s perpetual virginity will not allow this reading. [I, for one, think that Limited Atonement is exactly this kind of teaching.]

§ the plain meaning of the text
Theology might be seen as a way of subduing or domesticating the text of Scripture - of putting it in its place under or alongside a more important source of doctrine, such as Reason, Tradition or Experience. Or it may be that one text, or theological idea is allowed to condition all the others. In current church debates about women’s ministry for example, the principle of gospel equality is held to override texts that ascribe different roles.

§ A commitment to an empirical method
Further, there is rightly enough a commitment to the epistemological empiricism of our Anglo-Saxon heritage. Simply put, we tend to see that the answer to any theological question can be found by listing the biblical data, perhaps leavened with some historical background. On the other hand, without explicit Biblical data, we become suspicious that we are engaging in speculation.
Personally, I think that Biblical scholars have been part of the problem here, with the greatest of respect. They drag their heels when it comes to theology - from both the conservative and the liberal end. [What are you doing, guys and girls?] We need to release the bible from its captivity to biblical scholars, actually...

so: why we should "do" doctrine:

i. because we all have a “theology” whether we like it or not - so better an informed and reflective one than not.
There is no reading of the Bible that does not already rest on theological assumptions. Doctrine enables us to test these assumptions honestly. It is frankly dishonest to claim that we can do without theological reflection. “Just reading the Bible” is a myth!

ii. because it is an evangelical necessity: the ancient gospel is being preached in new situations and so requires fresh and faithful re-articulation in every generation.
In particular, the demands of our time are enormous and require responsible and creative work.

iii. because it helps to inoculate the church against false teaching.
Doctrine is our “defence against the dark arts.” After all, the Jehovah’s Witnesses claim the principle of “Scripture alone”. We need an understanding of doctrine in order to tell what is truly Christian.

iv. because it is a pastoral necessity
Doctrine enables us to address the teaching of scripture about the reality of God to the questions, the trials and the sins of our flock (and of course to our own lives).