The grave error here is that the entire premise of the article is built around the legitimacy (or illegitimacy) of “Calvinism”. Further, Sproul did not say what the author puts in his mouth (cessationism). But, it makes for good controversy...just no light.
SeekAndFind made IMO an excellent post on the first version of this thread (and again here) regarding the Biblical test of true prophecy. In short, any alleged post-apostolic prophet needs a verifiable 1.000 batting average in regards to predictions AND Christology, or he's a false prophet. Can anyone cough up such an individual to demonstrate why Sproul's experience is wrong?
Christian Mysticism Within Evangelicalism
http://deanbible.org/Media/Documents/Pre-Trib2012/Papers/Ken%20Hornock.pdf
Cessationism, Revelation & Prophecy
http://sharperiron.org/article/cessationism-revelation-prophecy