spider bots and other multi-legged bots would probably be much more useful for scouting.
Regarding military tool angle, Giant Robots are called targets.
When I was a child I used to crash my toy metal cars together with no damage what so ever…
I would think this is the way to go too. Once the research into plastics that can approximate muscle functionality with more power pays off, build something vaguely like a giant scorpion with a 120mm cannon and a .50 in the tail, program it to obliterate anything that looks vaguely hostile, and send 500 of them in the general direction of the enemy while a few hundred UAVs provide aerial support. Then watch it all play out live on Google Earth 6.0 Military Edition while giving the occasional command update.