Before we look into the justification for such a policy, note that it's aspirational. Those journals did not prohibit works shorter than 40 or longer than 70 pages; they indicated that
The vast majority of law review articles can effectively convey their arguments within the range of 40-70 law review pages, and any impression that law reviews only publish or strongly prefer lengthier articles should be dispelled. Ultimately, individual law reviews will have to decide for themselves how best to resolve these concerns.
(emphasis added) Admittedly, some pieces will fall outside these parameters. Some authors have rightly objected to anything that might begin to look like a quota. I don't think that's what is proposed here, although some management-efficiency guru somewhere is probably going to convince at least one board to adopt such standards for the sake of "measurability" and ease of winnowing the slush pile.
In any event, I want to note one serious problem that lurks under the controversy. It's sort of the converse case alluded to by Professor Madison:
No, the problem with the law review edict is that writing is what lawyers do. ItÂ’s what weÂ’re trained to do, and itÂ’s what weÂ’re paid to do. The written word is the coin of all of our realms. Law review editors telling law faculty that they write too much is like Emperor Joseph II telling Mozart that he used "too many notes."
(italics in original) No, it's nothing at all like Mozart—although, given the particular piece in question, the Emperor had a point; it reminds one more of the greater excesses of self-referential postmodern fiction than perhaps it should. Whether one's taste goes to Mozart or not, it's very difficult to claim that he was not a master of musical composition, or at least of the musical composition of his time. One simply cannot make the same claim about lawyers, or even law professors. The "training to do" is virtually absent after the mandatory first-year class in law school, and it shows. Just look at the example I discussed a while back on string citations and footnotes!
Bluntly, the class {lawyer} (and, for that matter, the class {law professor}) consists too largely of marginal-or-worse writers, and certainly writers whose training has deemphasized brevity. Just think for a moment about that length suggestion put forth by the law reviews, and work out a few numbers. In standard law-review format, one will find around 360 word-units per printed page, assuming that 20% of the page coverage is in footnotes (which is close, if not a bit of an understatement). Forty pages then works out to somewhere north of 14,000 words—that is, more than the maximum length of a principal appellate brief under the Federal Rules of Appellate Procedure, and without having to include a statement of jurisdiction, statement of facts, summary of argument, or standard of review in that mass of verbiage! Seventy pages would be around 25,000 words. While some arguments certainly do require more (or less) space than that, I agree that the "vast majority" of works that should be put into a journal article will fit in that range. So long as there is an adequate allowance for outliers, I think the proposed parameters are eminently sensible.
This gets back to the problem of the identity and training of law review editors. Perhaps if the profession of law, and more particularly the profession of academic law, were not so hostile to individuals who had substantial careers and nonlegal graduate work before coming to the law, this would be less of a problem. Perhaps I was spoiled by my own law review experience: All three Articles Editors and the Editor-in-Chief had been out of undergraduate work and in the real world for at least three years before law school, and we held a total of eight AB-and-above degrees among us ranging across the humanities, the social sciences, the natural sciences, and engineering. Perhaps, though, I should expound upon this another time, as it's probably going to be misinterpreted in this context.