Everyone is looking at this wrong.
The light saber is LONGER then other light sabers before it. How does this happen? Simple, the cross guard portion is very short, the extra length comes from the cystal/s that generate the cross guard portion. The cross guard portion actually continues inside the hilt and up through the main blade, making it longer. As far as it being chopped off, first of all with a longer actual blade you would have a massive advantage against traditional sabers (you can hit them before they can hit you), second the hilt could be made out of a material that is resistant to the light blade, so it would naturally stop another lightsaber (just like a normal cross guard would do for a blade). The reason the whole hilt is not made of it is because you need the extra crystals to extend the main blade, and if you capped off the sides it would unbalance the weapon (if the hilt was as long as the actual lasers). Also it does allow for some additional blocking techniques with the laser portions of the hilt, and possibly even more damage if you where to throw the weapon.
As far as not being able to actual USE a lightsaber, non jedi have done that in the books at least and it's totally not true that you could not train yourself to eventually use one in real life without cutting off limbs. Just like any other skill, it would take time and practice, but you could do it with non-leathal versions first (just a beam that is hot, but would not cut through your skin). Practice makes perfect and with enough practice you could learn to control a light saber in real life.