More hours? Come to my school and see how many hours and DAYS are wasted time due to the classroom being 90+ degrees. No teaching or learning occurs on those scorching days because both students and teachers are just trying to cope. The curriculum on those days is drink, drink more, go to the bathroom. Dizzy or nauseated? go to the nurse.
More students? More students means less time I have to work with each individual to get them where they need to be or to help them achieve even greater skills and understanding. More students means either I don't give the neediest the full amount of time and attention they need, or those who are at the top of the class are left on their own since they don't need extra help. More students means I can't even give their written work the attention it deserves and give feedback to improve it.Fewer students means I can reach both groups and give them tutoring or enrichment so they can both raise achievement and reach their own potentials.