One major disadvantage in the Roman system of education was that

the poor would not receive formal education like the rich who had private tutors and attended what we recognize as schools. The poor would only learn the basics of reading and writing. This is a disadvantage because the poor were unable to more up social class because they were uneducated.

Explanation:

classical republicanism, also known as civic humanism, is a form of republicanism  developed in the renaissance inspired by the governmental forms and writings of  classical  antiquity, especially such  classical  writers as aristotle, polybius, and cicero.