I'm certainly no proponent of any of the literary solutions to the synoptic problem. As I argue in Structuring Early Christian Memory, as well as in an article I'm writing for JBL, there are very problematic assumptions underlying the confidence with which NT scholars have employed literary paradigms to pursue source-critical agenda. Even so, as I read Stein's article on the Synoptic Problem in Dictionary of Jesus and the Gospels, I'm amazed that the Farrer hypothesis isn't even mentioned in the listing of the "most common explanations involving interdependence" (786). Apparently the demonstration of Matthean and Lukan independence on p. 790 suffices to dismiss Farrer (and Goulder and Goodacre) without even mentioning them!
Again, I'm no disciple of the Farrer-Goulder-Goodacre school. But Goodacre's discussions of the Synoptic Problem (admittedly, most of his writings are post-1992) are extremely careful and well-argued. The fact that the institution of source critical inquiry apparently doesn't (or didn't) mind ignoring a major challenge to its dominant narrative suggests, at least to me, that that narrative and its influence over gospels scholarship is susceptible to serious, even catastrophic, blind spots.