Pure speculation at this point, but this model has me so so hyped. The idea that you have scout two to start with, and can sprint into the map and place charges gives you so much map control.
Placing them in:
-choke points,
-areas you maybe flanked
-close to barricades
-alleyways or space between buildings
Their strength will totally depend on the amount of terrain on the map, and impassable terrain too, but just the concept of them has me giddy. Just ruling out areas of movement for the enemy unless they wanna suffer severe casualties. A real problem for units with a compulsory move too when countering speeders.
I can see myself bringing 2, 2 man specialist squads of Proton Charge Saboteurs in future lists...