ArneHD
Just a little bit mad
Perhaps the shield could be included as a promotion? In essence shielded units have high base strenght, but recive a weakness in/on desert (to represent turning their shields off, this ought to be pretty severe since on of the main reasons why the fremen are so good is that they do not compensate for shield when they fight) and perhaps a weakness against lasers (you know what happens).
They would also have a high resistance to ranged units and some resistance against melee units
They would also have a high resistance to ranged units and some resistance against melee units