Well to begin, I thought Melbourne High was well known for having great teachers along with a curriculum which was based around students being able to be flexible and learn in their own environment? (Which results in their ridiculously high median ATAR every year?)
I disagree (inb4 hate from AN community). The teachers teach much the same as uni tutors do. They're more guides rather than teachers (generally). Sure you get the odd teacher who is super motivated and will teach you heaps, but they're not all like that.
Other than the physics dep (this is when I was there), teachers seem to have a really good understanding of the courses, but leave it up to the students to do a lot of self-directed learning. Personally I didn't mind, because being spoon-fed isn't a great life skill and we were already given so many resources (both academic and co-curricular) to make up for it.
Median ATAR is high because you've chosen the "best" students from year 8 as a "selective school". Of course the ATAR median is going to be high, bit of a no-brainer there.
Having said all this, I loved my time at the Castle on the Hill and wouldn't trade those years for anything <3