When the game changes, so must the rules, new ROE and LOW

Unmanned warfare is very new and different than the fighting we are used to. For our old warfare, we relied upon the ROE (rules of engagement) and LOW (laws of war) to dictate how one should act in war and when, and only when, someone should begin a war. This not only prevented unnecessary warfare, but also gave other nations the ability to say "You stepped over the line and did something wrong, so we are going to oppose you until you stop." With unmanned warfare, doesn't it make sense to modify these documents for the new method of warfare? If we were going to write new ROE and LOW, what are ethical and legal requirements that would need to be listed?