Its a fast attack recon vehicle, just unmanned. It also can provide an "eye in the sky" for other units. I think its main gun is an Assault Cannon-like device.I seem to be currently drawing a blank.
Is the drone supposed to be a recon unit or is it supposed to be an explosive that stalks you then blows?
If its a reconnaissance: I can figure it would have something similar to a sniper rifle and a bonus for hiding in terrain.
If its a floating bomb: I picture it as being a floating orb that moves like a beast (extended charge range) and like a jumper (moves over terrain). Once it gets into base to base contact with an enemy model it will explode. I figure place a large blast template with the orb as the center.
I think that the sacrifice of a model is a fair exchange for a large blast template.