Slap and Bill:

If you drop a hand grenade accurately from however high you choose, it is still just a hand grenade. And you may be able to put it precisely on a target but you have to be able to see and identify a target. If there is something between your sensor and what you want to hit, a tree a roof or a rainstorm, it won't matter how deadeye you can be because you can't hit what you can't see. No matter anything else, it is still a very expensive way to deliver a munition.

I realize the tech is advancing quickly but certain things don't change. The item Bill referenced still needed radio reception and transmission to work. It was powered by batteries which severely limit the payload and endurance of any aircraft. Something little like that will work in well inside a building but can it handle a 20 knot gusty wind? Computational power and control tech advance but there are still the problems of power, weight, weather and being able to find something that is hiding. David is right, all this may be what it is cracked up to be someday, but that day may be a ways off.

David, an even better example of the phenomenon you mention are air to air missiles. They are quite deadly now but in the 50s people expected them to quite deadly immediately and made decisions based on belief. It took 40 years for the missiles to get there.