I would love an attack area function for artillery, and also the ability to limit artillery to only attacking within a certain quadrant or at a certain minimum or maximum distance. So much more convenient than constantly re-targeting artillery to make sure it is firing for maximum effect and not cutting swathes through one's own army when the enemy gets too close, or futilely trying to swivel around as enemy cavalry gallops past it (often right before the rest of the enemy cavalry gallops straight into it).
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