Questions About Progressive Revelation

Maybe I missed something in all of my studies. Or maybe I just haven't read the right book. I believe in progressive revelation. I don't know many people that don't. No Orthodox Christian believes in "progressive revelation" the way that Mormons or Jehovah Witnesses do though. So what am I to make of the general Evangelical consensus on progressive revelation?

I've been in a lot of interesting conversations about it recently (mostly because of hermeneutics) but I don't know that I've ever been given a definition that matched my view. How many differing views are there on progressive revelation? And how often do these difference affect church doctrine that spans the "two testaments"?

I now believe that it is this concept that determines if one is a theonomist or paedobaptist. How strongly one puts stock in Old Testament "proof texts" plays a big role in these debates. Tendencies towards typology are often based on ones attitude towards the Old Testament's importance.

With all of these things flooding my mind, particularly over the debate on baptism, here are some questions I have been asking myself.

1. Do we define "progressive" in terms of canonical order or chronological order?
2. How important are modern (and secular) textual critics in determining the importance of chronological order?  
3. When do the Scriptures "progress" into the "new testament"?
4. How often do we let theological presuppositions determine the importance of the testaments?  
5. What textual, and hence Scriptural, warrant is there for "two testaments"?
6. Does the New Testament "progress" on every subject mentioned in the Old Testament?
7. Does the Old Testament mention every important theological subject? 
8. Given the typological nature of the Old Testament, with what certainty can a subject be "mentioned"?
9. Does the idea of "progress" refer to clarity or addition?
10. Can one truly "progress" in either sense with a typological example? 

These are all important questions that I am still theoretically dealing with. However, one should not be deprived of an opinion simply because one is wrestling with questions. We should not be afraid to voice our current opinions or repent of those opinions when we change our mind. So what is my current opinion?

I have come to the conclusion that those who lean toward "progress" meaning addition and alteration do a great disservice to the Scriptures. By this I mean, that the study of any topic must begin with the Old Testament. Little, if not nothing, can be seen as new in the New Testament. In other words, there is little to nothing which is not spoken of in the first half of the church's canon. Despite this opinions, which some might unwittingly share, the tendency in most church people today is to begin their study in the New Testament.

If this is solely for the sake of didactic clarity then no great harm is done. However, in many cases the didactic can be awfully construed when removed from the Jewish context of the original authors. When study of this type is done without consulting the Old Testament, no greater skewing of God's immutable and inerrant revelation can come close. The Christian must understand that we once also were Jews before Christ. We once had only the Old Testament before Christ. And both Christ and the Apostles relied solely on the Old Testament and the Holy Spirit for the inspired and inerrant didactic of the New Testament.