One of the reasons why classic school education is so criticized is that the level of knowledge which it offers is quite mediocre. Thus, a lot of students are unable to develop their creative potential. What is a more, a lot of them are not even aware that they have creative potential.
The thing is that classic schools quite often provide basic knowledge which a person will need while working at some quite popular position. However, no one teaches a student how to boost their creativity or how to develop their unconventional thinking. As a result, the person may not even realize that they have a talent for something.
Speaking about the ways in which it is possible to tackle mediocrity in schools, the most important thing to do is give students creative tasks as well as to challenge them more often. The more unconventional the assignments are, the better the results will be. Apart from that, it will teach students how to find a solution even when it seems like there are no ideas at all.