I'd hard to disagree with you here.
Don't get me wrong, I do actually agree with brother AMR's position that the traditional Presbyterian view is some form of cessationism (and here we can get into trouble--and I think AMR and I already have--if we don't define what we mean by cesationism--was it an absolute cessationism (hard) or a moderate one (soft), or either of the two?). I also hold to a cessationist view in line with my PCA church. But in any case, I still think he's overstating the case. The cited portion of the WCF relates to Sola Scriptura. It simply does not address the full range of spiritual gifts and it does not define "prophecy" as something which must introduce new doctrine--i.e. that "prophecy" is something which is always "Special Revelation" in the same sense that Scripture is, and thus, is on par with Scripture. It just does not cover the whole range of issues we find in the modern debate.
So I just don't think we can reasonably make such definitive claims regarding the bigger question of spiritual gifts (especially when it comes to a specific types of cessationism) and I certainly don't think the WCF is a good place to go to in order try to make it. I think it's better to simply refer to the Reformers as explicit examples of folks who held to a cessationist view (of some sort), then move on to Scripture. I really don't see the need to spend so much time arguing over interpretations of traditional documents and the beliefs of earlier Christians when we don't find an explicit view expressed in them, especially on this issue. I think it's safe to say that Calvin was clearly a cessationist of some sort. Yippie! We're not all bound to believe everything Calvin believes. But even if we felt the need to reconcile Calvin, this particular issue would require an explicit expression of hard cessationism (which from everything I've encountered, is either hard to come by or simply not to be found) to really show that continuationists are out of sync traditionally with Calvin (or anyone else), because showing that Calvin or the Westiminister divines were "soft cessationists" will not satisfy continuationists who will just claim, "cool, but they
didn't completely rule them out and THEY'RE BACK NOW!!!" So why bother? Go to Scripture and go to the decisions of traditional and modern Presbyterian churches on the issue.
I.e. I think it's much simpler to say that Presbyterians have traditionally held to some form of cessationism as did the magisterial Reformers, and that today, most conservative Presbyterians such as the OPC and PCA hold to cessationism (as I understand it, the OPC explicitly to hard cessationism and the PCA allowing for various ranges within cessationism) while more liberal Presbyterians such as the PCUSA and EPC are open to continuationist views.
In any case,
this book will probably be useful in learning more about the views of the Westminster divines view of prophecy and special revelation.