It would break my immersion more to have invulnerable children in the game.
And I still don't get why this is. If you don't plan on hurting them it won't effect anything in your play experience. If they implement it where they run away and hide if you draw your sword they'll still technically be invulnerable but you won't even get a chance to hurt them so THAT won't effect anything in your play experience. You can easily pretend that they're NOT invulnerable or set aside your knowledge that they are-it's just a GAME MECHANIC-does the fact that you have to press a button to swing your sword also break immersion?
@Infiltrator
It's because Skyrim is a mainstream video game available on consoles and Bethesda wants to avoid the inevitable moral outrage that would occur if their game allowed you to do that sort of thing. Fallout 2 could do it only because it was a PC-only game and PC games weren't mainstream back then (they still aren't, aside from some MMOs like World of Warcraft).
Getting back into the subject of werecreatures it'd be nice to see more types of werecreatures-or perhaps including the ability to add new werecreatures and such through the new Creation Kit.