Lightsabers are a health and safety nightmare.
Lasers are invisible in regular atmospheric conditions, have no mass (to be able to deflect even other lightsabers), can't really stop unless you put a mirror in the other end to reflect it back. If they ever come about, I'll personally kill Darth Vader with the backside of a cd.
I think they can get around that by saying "its plasma" or smth like that...but then the lack of a cooling mechanism would be very problematic indeed. It would probably need plugging into the mains too..SO yeah, the force!