I'm more worried that he will "seem fine," because he's sweet-natured and a pleaser. To be 100% clear, I don't actually care if he learns anything in K. (Well, better penmanship would be nice and completely on-target in terms of what I woudl expect.) I just don't want him to be miserable.
The teacher-pleaser thing was a problem for our DS. He was always extremely well behaved and never would complain to the teacher. We got the complaints at home and the teacher could hardly believe us when we said our DS was unhappy, since he appeared perfectly happy at school. Also, our kiddo was not a hand raiser - he didn't like to stand out at all. So the teacher even thought he was BEHIND verbally, which is really his strength.
ETA: What finally changed the teacher's mind was seeing the results on the school's own tests -- they let DS do MAP testing with the 2nd graders, and when he tested well enough to pass the 3rd grade state assessments (as a kindergartner), they saw him.
