My #2 had exactly the same experience at this age (preK). Complaints that there was "not enough learning" happening, even though the design was mainly play. But if a little one is ready for more, there is a limit to how much dress-up, blocks, sand table, and trains one can tolerate in one week.
We did end up pulling out to homeschool. No reason you can't change the school arrangement next year, either. Kids' needs change from time to time, so we should feel free to change their instructional settings as well.
