The validity of the structured input / output activities rests entirely on the conceptualization of a process whereby form is unconsciously mapped to function (described as intake for input, access for output) and the belief that having students engaged in this process is the most effective way for them to learn, and maintain a working knowledge of, the grammar of a foreign language.
The studies presented in the article quite convincingly demonstrate this validity, though I would have liked to have known what (if anything) the students being examined were doing at home. For it seems to me that, as far as students’ ability to work on their own is concerned, the benefits of paradigmatic grammar instruction actually go beyond the realm of mere affect. What of the manner in which paradigms (made usable by traditional classroom grammar instruction) provide students with a way of experimenting with a foreign language during content-driven writing exercises completed outside of the classroom? What of the manner in which they impose upon students a (somewhat) transparent horizon of correctness/incorrectness that forces them to go about their writing with a specific type of self-monitoring and, as such, rigor?
Ultimately, I am suspicious of the rather non-interactive understanding of the process of mapping form to function that the article presents. It seems to me that there is more going on here than the mere unconscious intaking / accessing of the “correct” form, and that the apparent agency of out students’ conscious cognitive / hermeneutic activity in this process speaks quite strongly for the continued importance of paradigmatic grammar instruction, or at least of finding ways to make paradigms accessible to students in an clear and compelling manner, grammar videos featuring Darth Vader, heartbroken instructors, and canned meat, for example :-).