Personally, since I knew they wouldn't fire me and I worked at a relatively small branch and saw the students often, I told the students precisely when they were wrong and how. Tactfully of course, but I didn't engage in any 'Well that was just GREAT, but shall we try another way to say it??' because it wasn't great, it was wrong, unnatural sounding and it needed changing, period. Its just not realistic to expect them to improve without a little conditioning, a little carefully applied reward/punishment if you will. You need to explain why something sounds unnatural because the direct translation in their minds might sound perfectly reasonable. You're teaching them to think in English. And I think the students, whether they're kind of uppity and take themselves too seriously or not (which is the fear of the staff, that they'll somehow become insulted or turned off), will ultimately appreciate your teaching if they perceive it to actually be teaching and not patting on the head.
Classroom dynamics are going to be under your control so your skill as a teacher will be the final word as far as what they learn is concerned. Getting them to learn however does NOT require you to coddle them though, no matter what the staff say. If you're a good teacher they'll improve and trust your methodology.
I think the biggest sell-out is for teachers to view the students as sheep and assume that the NOVA method is all they need to worry about teaching. Listen repeat, listen repeat, now lets try a roleplay, etc etc. The LMP (I forget what that stands for but its the teacher guide basically) is just that, a guideline, its up to you as teacher to flesh it out, personalize it, change it, make it applicable and relevant, etc. From there you have a lot of latitude as to what you can present to your students so in that way I personally didn't feel so frustrated by the NOVA effect. But the possibility is definitely there.