Hello,
I suffer from carpien tunnel(basically it hurts when using a mouse too intensively) and soon every body playing this game will do too. The fact that you constantly need to click to attack is really hard on the hand.
The worst offender is “light melee attack” and shooting the last gun or semi auto as veteran.
Its just not healthy and I hope you guys remember this thread once you start having issues with your nerves.
I don’t see a good way for them to solve this for weapon light attacks but I really hope they add it to the semi-auto guns in this game at least. After a while my fingers just start to hurt and I’m pretty sure if I continue I will get lasting damage to my hands 
Read RSI
Only real way to solve this would be to add an accessibility option to toggle that holding does light attacks and then bind another button for heavy. From what I’ve read about other game input stuff it sounds like it’d be hard but definitely something they should consider!
Potential solution, if your mouse has software to allow you to customize its bindings, you could rebind mouse 1 so holding it makes it perform a repeating macro that clicks left click over and over, and then rebind a different key on your keyboard (or mouse if it has side buttons) for a separate macro that holds the button down for heavy attacks. Hope they add something to help!