considering good teacher is rarity it's pretty bad idea, without looping everyone can experience him at least for short time, with looping some may never met such teacher
in kindergarten I couldn't wait until my kid gets through a year to get better teacher next year, now in primary school we are first four years stuck with oldest teacher in school, we won a "lottery", at least I teach my kids not to take teachers very seriously because with these salaries nobody competent will keep teaching (and don't get me started 95% teachers in school are females, very healthy ratio to have diverse views presented), same goes for telling kids if they won't study good at worst they can always join police force where bottom of the barrel ends
in kindergarten I couldn't wait until my kid gets through a year to get better teacher next year, now in primary school we are first four years stuck with oldest teacher in school, we won a "lottery", at least I teach my kids not to take teachers very seriously because with these salaries nobody competent will keep teaching (and don't get me started 95% teachers in school are females, very healthy ratio to have diverse views presented), same goes for telling kids if they won't study good at worst they can always join police force where bottom of the barrel ends