>>>It appears to me that it makes an easy target for a terrorist with a rocket propelled grenade.
That's not the point. You expect a first generation prototype to be large. Later models will be reduced in size and increased in power assuming the M 1 meets expectations.
Note, what can hurt on a low setting will kill at a high enough setting.
Exactly. It's definitely gotta be a microwave based weapon. So, hook it up to a large enough energy source, and you have insta-boiled 'insurgents'...erm... 'terrorists'. Can you imagine a focused microwave beam strong enough to boil any water/liquid it hits ? That'd make for a fantastic anti-personell weapon. No ballistics (can't miss, really), direct fire, zero travel time.