My grandmother used to reminisce about spending the first five minutes of Spanish class practicing rolling her r's. My grandmother would be proud — the ESL classroom doesn't just spend five minutes on English pronunciation, we spend an entire class on it.
This is because in Japan, repetition is the main strategy for teaching kids. Like writing kanji over and over, it is thought that if one practices pronouncing a word over and over, it will eventually become pronunciation perfect. But I believe students would benefit more from targeted pronunciation exercises that isolate the foreign sounds they have to make than just from repetition.
The problem with teaching pronunciation is that you're trying to teach students unnatural sounds, kind of like attempting to teach them to bark or sing like a bird.