I think using a title is a good idea, to distance the teacher from the kids and hopefully command some respect.
I don't see why they need to be "Sir" and "Miss", but I do think they need to be already established in our language with some connotation of respect to avoid mockery when the schools and teachers insist upon it. "Teacher" does not command respect in this country, and trying to enforce it as one will inevitably backfire.
I get that there are some very vocal people who want to pretend that boys and girls are identical and would grow up so if society didn't point out the differences, but some things that do distinguish are useful and you need to have a viable replacement for the thing you're scrapping.