The "Chance to Miss" mechanic isn't the proper way to increase the challenge in this game. There is no indication that the player CAN miss, and there are plenty of comments regarding how silly it is for close range weapons to miss.
The more accepted mechanic would be the "increasing reticle area", as it is more generally used and more feedback can be given to the player. Feel free to explore other options, but a MISS popping up just doesn't quite cut it.
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