Some thoughts on the topic of revelation, disconnected because they are still forming in my brain:
1. In the NT, revelation is substantially an eschatological concept. In the Pastorals, the appearing of Jesus is a technical term for his return (1 Tim 6:14, 2 Tim 4:8, Titus 2:13 etc.); this echoes other Pauline (2 Thess 1:17) and Petrine (1 Pet 4:13) passages about Christ being revealed at the end. Fundamentally, revelation is a thing belonging to the new age which is not yet consummated. Therefore, the revelation of God is an especially appropriate subject for meditation in advent, and looking forward to seeing God is at the heart of advent devotion. 1 Peter 1:8 captures the theme - we have not seen him, but we love him, and therefore we wait to see him.
2. Revelation is an eschatological concept even when applied to the ministry of Jesus. The end of John's gospel captures this, when it talks about Jesus resurrection appearances (e.g. John 21:1). However, the concept is present earlier in the gospel narratives, especially at the transfiguration, which is a preview of the resurrection appearances. When we talk about Jesus revealing God, are we talking about the eschatological light - the glory of the God-man in the coming age - breaking into this age? Even those who saw Jesus did not necessarily encounter this sort of revelation, but many who did not physically see him have encountered it.
3. Revelation, then, is not a static thing. It is not something which is always there, but it is something which breaks through. It is the new story which starts in the middle of the old story.
4. Because revelation is the story of Jesus, it is right that our advent meditations look backward as well as forward. The light has begun to shine, the story has begun to be told. It makes sense that advent terminates in Christmas, every year asking the question: will we see him this year? But also knowing that whether we do or not, we can see him in the apostolic testimony to his life, death, and resurrection.
5. Jesus is uniquely revelatory, because he is the new story and the light in himself. For something to break through - for a light to shine in darkness - it has to come from without. God stepping in to creation would be - is - a new story in the midst of the old and a bright light in the darkness. This is about incarnation. It will not do to begin our understanding of revelation anywhere else. If there is light anywhere else, it is because it comes from this source; if the old story starts to show some hope and some glory, it has been invested with it by the new.