That's one of the recommendations from the MLA's president for "reforming doctoral programs." It's not clear to me if he understands time-to-degree as including the MA, or not. In any event, I finished my Ph.D. at Chicago in five years, including the MA, but my situation as a graduate student was thoroughly atypical: not only was I fully funded for the entire haul, but I also did zero independent teaching. At the time (mid-90s), you had to be in your sixth year of a degree program to teach your own course; I led two once-per-week discussion seminars--and only got the second (students at the time were generally kept to one) because I pointed out that I was about to be let loose upon the world with no practical experience worth discussing. Of course, once I actually finished, much to everyone's astonishment ("Wait, you're done." "Yes, I said I was going to be done."), I turned out to be pretty much unemployable for some time, there not being any jobs for people who really haven't the slightest clue how to teach. (Through certain backchannels, I got feedback from one committee, who thought I had given an excellent interview. They also thought I would probably explode in a pile of smoking ash if placed in front of their students.)
This is all another way of saying that the current demand for faculty who have a basic grasp of pedagogy is probably incompatible with completing a four-year degree, which presumes a student doing not much else except coursework and dissertating. My department's own MA, which predominantly serves teachers working on their credentials, takes two years, and teachers who are employed full-time often need to take longer to finish. By the same token, if, as the president suggests, universities should "provide the broad professional development and skills that, while central to an academic career, can also be transferred to other paths," you will very likely also need a degree that takes more than four years to complete, unless you somehow expect to cram in two forms of job training at once--and, I suspect, do both rather badly.
Meanwhile, none of this addresses the two pink elephants in the middle of the room, wearing tutus: the lack of jobs for people who have doctorates, and the likely irrelevance of a doctorate in English for many other potential careers, aside from the usual writing-intensive suspects. (By which I mean that Ph.Ds in English wind up in other careers on a frequent basis, but there were probably much less time-consuming and, quite frankly, much less emotionally/psychologically painful paths to get there; I don't think a four-year Ph.D. changes that.)