Why did you listen to your prof's advice that assigning a piece of in-class diagnostic writing would be helpful? Of course it would --- and it would be more work for you! And why did you then assign a practice close reading assignment as homework as well? Now you must actually read and comment on them, you yutz!
Sigh --- I should probably comment on them right now in order to give them back in time for the students to prepare for the midterm ... or ... (she says, getting a maniacal gleam in her eyes) I could claim that the practice of doing the close reading is what they really learn from as much as the correction of it. Hmm. Part of the benefit of getting samples of their in-class and prepared work is that I can see what they need to work on (Prof suggested the most important aspect of it was catching and referring people with learning disabilities or major writing problems or ESL problems to the appropriate tutors), but part of what makes the midterm great is that it, frankly, come back to them as a wake-up call, that this will not be an easy class and they will need to shape up now. It's harder to do that if you've already OK'd their writing --- a lot of students take any sort of response besides "do it over" as "this work merits an A." Sigh --- plus there's the problem that, now that I have writing samples in my hands, anyone who does something wrong or awkwardly on the midterm who I didn't correct and warn beforehand is, in my mind, sorta justified in complaining about a bad grade.
On the other hand, here is a panda.