ghosta,
I think 1x1 is the indivisible smallest unit of space. Having something occupy fractional space just invites all sorts of trouble.
The idea itself, however, has merit! In most ways, the philosopht is that aliens are tougher, better than humans in a 1:1 comparison. The concept of a fllood of weak critters, something killed by a single pistol shot (i.e. one hit from anything) is very neat.
Having a bunch of those small, cheap scouts run around would also explain aliens' "omniscience".
Come to think of it, how about humans get to develop something like that too - small, not too expensive platform that can scarry quickly around and relay video. At early stages having the little things to do the scouting would've been great. maybe limit to two per mission. Otherwise, the battle field becomes flooded with tiny spidies.