1) What would it mean to save the world? To bring about, however incrementally, my vision for the world.

That's not the meaning of 'save the world.' I just took it for granted that the preservation of human-like things would probably be part of your vision.

2) What does it mean to live a fulfilling life? To get what one wants.

Better: To get what one would most want, given perfect knowledge, computational capacities, and reasoning skills. (At least, this would be closer to the optimally fulfilling life.)

These two answers seems to place very great confidence in my (or my students) vision for the world, and my (or my students) desires.

We're humans. We don't have anyone to appeal to but ourselves and each other.

So by saying you don't want to persuade me to adopt your own vision for the world, etc. it seems to me you skipped the most important part of the question.

Sure. Though you can read a fair amount of that out of what I did tell you about course layout.

if I teach my students to be more effective at getting what they want and bringing about their vision, while what they want is harmful and their vision is terrible

There are two questions here. First, are people's most profound and reflective goals in the end perverse and destructive? If so, then humanity may do better if kept in ignorance than if enlightened.

Second, can we teach people to re-evaluate and improve their values? Their current vision may be 'terrible,' but part of teaching people to understand how to attain their values is teaching people how to recognize, assess, and revise their values. This is an essential component of Part 3 of the course structure.

Acting may be very dangerous. But doing nothing is far more dangerous.