Putting the doctrine of revelation underneath Pneumatology does a couple of other things.
(1) It says that the doctrine of the Trinity governs the doctrine of revelation
(2) It says that we know God only as revealed in Christ through the Holy Spirit
(3) It says that the doctrine of revelation is better entitled the “doctrine of God’s self revelation”
(4) It says that the purpose of revelation is to bring one into fellowship with the triune God
(4.1) That said, it isn’t just to inform the mind or direct the will.
(4.2) I think, too, that this connects with the thread of Pneumatology that sees the Spirit as the Spirit of Wisdom; so this gets into the whole idea of wisdom literature, Jesus as a teacher of wisdom, etc.
(5) It says that metaphysical naturalism or classic deism are wrong
(6) It says that trying to discover a “proof for the existence of God” outside of revelation is ridiculous. Such proofs would never produce a Trinity anyway.
(7) It grafts the doctrine of revelation onto the renewing/re-creating work of the Spirit—which is fundamentally eschatological.
(8) It asks interesting questions about how to read the Bible and about the connection between written word, spoken word, and lived experience—in other words, it gets some head scratching going about hermeneutics.