They need to see that there is mathematics beyond calculus and that the idea of proof is central to mathematics. As for attitude toward mathematics, I would hope that teachers would be aware that mathematics is a living subject where new mathematics is being constantly created. I would also hope they would be deeply aware of what I mentioned in the first answer, that mathematics is about ideas and the relations between them. And, of course, one wants teachers to like mathematics and be enthusiastic about communicating it. As for pedagogical approaches toward mathematics, I don't have very strong feelings except to be wary of orthodoxies.
Some students work best in group settings, while some work best individually.
Many students prefer more concrete applications, while others enjoy playing with the ideas at an abstract level. I would hope that teachers would be flexible and adaptable in their pedagogy. What first attracted me to mathematics was the fact that I was aware from a fairly early age that I could do it. After a month, we went back to the more traditional stuff, but my teachers and I were aware that I could do interesting mathematics. Every summer, there were math programs for talented high school students that I participated in, starting with the summer after the 8th grade.