I am of the opinion that both acquisition and language are essential to achieving fluency in a second language. I believe the two are interdependent, that there must be both conscious and unconscious practice of language and that the one feeds the other in a big ol' Ouroboros. I believe that there probably are people who do perfectly fine--better than they would otherwise--with strictly immersion, TPRS, or TCI and no grammatical analysis until at least Novice High. I also believe that there are those, myself included, whose acquisition is accelerated by the scaffolding of grammatical analysis.
For me, it comes down to brain theory. For years as an English teacher and through the New Schools Project, I was assured that scaffolding was essential for learning to take place and that graphic organizers were pretty keen ways to help the brain out. This was borne out by my reading of John Ratey's A User's Guide to the Brain. I consider conjugation charts a kind of graphic organizer that helps place new information in accessible files for our brain clerks.
Not all of my esteemed colleagues, or #langchat buddies, agree with me. And so we duked it out on a post-#langchat Friday night.