They've got it designed correctly for the change. There's now a physical hand guard that extends out on either side of the grip of the light saber.
And hand guards on regular swords aren't made of double edged, super sharp blades. Never mind that a lightsaber is much more dangerous than that. Clearly the only thing that would make sense is something like a sai, where the two guard beams are angled away from the hand like a V. Have them protrude from as close to the main beam as possible so there's nowhere that contact with the metal handle can be made. Hell maybe even have a normal metal guard below the angled beams so that your hand can't slip into the guard beams.
Look at the screenshot again...it has a physical hand guard above the grip. The extra beams extend out of the hand guard. They're for secondary defense, not protecting the hand from sliding forward. I don't think the sai was used for sword-fighting, so that doesn't really make sense for a lightsaber. Those were originally Karate weapons.
The hand guard is primarily for your own protection (prevents your hand from sliding forward onto the blade), while the horizontal light beams that come out of the hand guard can be used as a secondary means of blocking your opponent's lightsaber.
How come no other lightsabre has one? But seriously, any rotation of the wrist and that person's saying goodbye to their hands
Have you invented a new way for the wrist to rotate? Because it's not going to rotate straight backward into your arm.
Rotate wrist left or right = no contact with arm Rotate wrist forward = no contact with arm Rotate wrist backward = no contact with arm (due to inability of wrist to rotate straight backward...it rotates backward at an angle, so the beams would point to the sides rather than making contact with your arm)