Add acoustic sensors to triangulate enemy positions, coordinate with aerial surveillance, add ability for aerial drop to be deployed across battlefield, add control moment gyros to allow it traverse difficult terrain.
You could have them roll back to a base point for self-charging. To make them airborne you could embed the standard model in a quad-rotor "collar" and use the rolling mechanism for avionics and control. Really, you could base a whole micro-UAV/UGV system around some version of this concept.
I've seen the Arduino drone guys report they've been able to land within 6m of their target. Not perfect, but considering the whole shebang is built by hobbyists for a couple hundred dollars, I'll excuse them.
Oh this is some great brainstorming. All these components need care and maintenance as well, so instead of having specialized cleaners for every component, I propose a "kitchen sink" component.
Well. Speed is absolutely essential during CQB, sometimes to the point where a grenade is to slow. Grenades with PETN are already powerful enough. Especially during room clearing, when you don't want penetration through the walls. I don't think it's a very good fit.
Grenades have the disadvantage of having to be thrown, which means you need a guy standing close to a wall, which is why you don't want penetration.
FIBUA has the unfortunate tendency to produce a good number of casualties because of the requirement to get close. Anything that increases standoff range therefore, can reduce casualties.
Using something like this, you could "clear" a house one room at a time without actually setting foot in it. Use three or four in quick succession for each room. Even though you'd still need occupation via human to ultimately be victorious, the need to avoid the initial assault into prepared defenses will be a godsend.
If the weapons are truly smart, who has any use for an omni-directional blast like a grenade? Keeping with the ball form, it is more likely it would hop and shoot tiny bullets into the forehead of everyone in the room; it could use the same exact tech that cameras now use to auto-focus on faces (until everyone started wearing decoy faces, ala numerous examples in the animal kingdom).
One "Little Boy"'s tonnage worth of gun-toting quadricopters dropped on a busy city would probably result in more deaths than Little Boy itself did.
(the world is pushing heavily in these directions; scary stuff)
1. "Ball" has core of C4, surrounded by wire, etc. (i.e. it's a grenade with a bigger bang)
2. Add increased range.
3. Add ability to "bounce" (for stairs, etc)
4. Add firing mechanism.
You now have a movable, controllable grenade. Ideal use: Room clearance. Turn ball on, roll into target room, bounce to waist height, activate.
You could easily modify this with CS gas or such for lower lethality options.