The fundamental problem with Bultmann's method is not its inherent skepticism toward the historicity of the tradition. Occasionally he grants a good deal of continuity to the tradition; and skepticism is indeed part of all critical investigations. Rather, what is essentially problematic is precisely that his method does not work as a tool of historical inquiry. (Byrskog, "review of The History of the Synoptic Tradition" [JBL 122/3 (2003)], 554; emphasis added)
Byrskog goes on to demonstrate the unworkability of Bultmann's method; this is not simply dismissive invective. And so the blunt assessment is not only warranted but also welcome.