I remember reading his book "How shall we then live" about 20 years ago, but it did not strike me as particularly profound. I didn't think of his stuff as theology as much as it was apologetic and practical. That's why I think the term "Last Great Modern Theologian" didn't fit. That's why I asked the question. It seems to me that the Last Great "Theologians" came out of the Reformation era.
Now if he could have solved the Calvin/Arminian dispute through the application of love and logic (which to me it appears to have been his forte), then I think he might be entitled to that monicker. :-)
I agree that Schaeffer wasn't a theologian per se; he never wrote a systematic theology. There are audio tapes extant wherein he gives lectures on Calvin's Institutes; which is - in essence, the first Protestant Systematic Theology. He was most effective within the realm of applying Presuppostitional thought in Evangelism and apologetics. Schaeffer was only able to do this because he was well acquainted with Orthodox theology and philosophy.
With regard to what you've indicated in earlier posts- and also inferred from your tag line - I may be wrong, but you seem to hold to a doctrinal stance that is called "Amyraldianism"- which is an attempt to marry Calvinism and Arminianism together (what some jokingly call "Calminianism"). I found a great article, which you may enjoy reading, that defines what this doctrinal position is, where it originated; then, where it fails; both logically, and above all, Scripturally. You may read the article here =
http://www.apuritansmind.com/PuritanWorship/Amyraut%20Universalism.htm
I hope that you do read the article; it may be simply food for thought at this point in time; but may help you and other Freepers to re think some important doctrinal presuppostions as well :>)