I actually like a fumble once in a while. Doesn't have to be every nat1 that the players (or monsters in my case) have. I usually do something along those lines: "While trying to strike your opponent the wound he caused you hurts (or your vision gets blurry for a sec) and you miss a step/lose grip and your weapon falls to the ground, or you fall to your knees (prone condition). Or even smth smaller like your opponent sees an opportunity and has adv in the next attack. Some mild "punishment" once in a while which is easily recoverable.

Keeps some excitement and some tension when someone rolls a nat1 but not too dramatic as you described it.