Wow, you wrote so much!
I looked at how Cessady's revolver works. There was an idea to make quick shots without loading. But here the dilemma arises that the player will use it all the time both when dealing damage and when trying to heal. Therefore, it seemed to me that quick shots should be somehow limited, as I did with the charging mechanics.
In terms of speed, I think it is necessary to increase both the speed of regular shots and the speed of charging with quick shooting. I thought to give the player more time to concentrate on dodging when charging the revolver, but perhaps this is not necessary.
In terms of recoil, it seemed sufficient. I tested the game on several people and at first they said that the recoil was strong, but then when they got used to it, they said that it was normal. Perhaps because you need to adapt to it, a new player will not want to bother with this and just skip this mechanic.
Regarding the scale, there was an idea to make a scale like in Armored Core 6. There it is a stun scale, which when filled stuns the enemy and the player deals multiplied damage. Well, and just fast shooting would fill this scale faster.
Thank you for your feedback!