A drone moves faster, but I don't think that changes the calculations.
There doesn't seem to be a great interest in having (small) drones shoot things yet, all the current uses seem to be:
- drone itself is the munition
- drone is the spotter for other ground based artillery
- drone dropping unguided munitions (e.g. grenades)
"Large" drones (aircraft rather than quadcopter) seem to follow the same rules as manned aircraft and engage with guided or unguided munitions of their own. If the drone is cheap enough then "drone as munition" seems likely to win.
A drone moves faster, but I don't think that changes the calculations.