In the current era of No Child Left Behind, cutting back on summer vacation is dangerous. The incentives for just raising test scores at the expense of everything else is very strong for principals right now - if you don't raise test scores, you can lose your job. Schools are already doing too much test prep. A longer school year or more time in school will just turn into more time spent on test prep.

Outside of school, children do incredibly creative things, especially if you can give them the gift of unstructured time. This kind of learning is so much more important than practice taking reading comprehension exams.