One of major issues with CDPR's gameplay design is lack of good skill ceiling, lack of risk/reward fine tuned to their mechanics.
In Witcher 1, you had that three click combo ( with Geralt going:
HUNGH! HUNGH,HUNGH!! HUNGH,HUNGH, HUNGH!!! ) extremely simplistic and easy to use, and engaging... for about 2 minutes.
Witcher II: endless rolling back and forth.
Witcher III: heavy emphasis on evasion/movement, but without punishing or rewarding the player for precise timing of any action.
What you end up with:
anemic, extremely repetitive gameplay
, even if mechanics are actually ood ( perfect example of this is Nier Automata).
For slow mo it has to be integrated in a way that is more engaging than
Press x at any given time ( for easy headshots).
RE VI has special attacks like this:
This is automatically executed without any player targetting.
I would go for something similar, player executed gun/melee combos but with slow mo+manual targetting that player has to execute
precisely at the end of each animation, and within a brief time window ( or it breaks the whole sequence and cancels bullet time ).