I think that's a pretty decent approach!
I have a friend who introduces larp to teenagers on the street by doing something like that, but with a really immediate situation. He'll get a group of three and say "You are his/her boy/girlfriend" (points at other player), and you (points at third player) are the best friend. You (points at boy/girl friend) love (points at first player) but they haven't had time for you recently, so you slept with their best friend (points at third player). You..."
At that point he has more to say, but most of the time at that point the players are already ready to start yelling at each other already. Most folks can get right into the drama of that pretty quick.
Now, that's a pretty particular thing there. But maybe when looking at the settings you like, you can think about the key dramatic moments that aren't fighting? Like, for superheroes it's awesome to be like "that bad guy is trying to destroy the universe, and you two have to stop him using these three powers" and cuing up the Infinity War soundtrack. But you could also do the scenario to point at the moment just after, and be like "you just saved the universe, and one of you is dying, who is it? why? What do the rest of you say to them as they go?" and build from that.