I remember there was a mod for the first game, that prevented enemies from getting cc'd multiple turns in a row.
Aside from that, I feel like the best way to do this would just reduce the amount of ways to apply hard cc as already suggested. Or at least add multiple steps to it, like you currently have with shocked into stunned. As well as reduce damage on abilities that inflict CC, so you have to decide between damage and CC.
As for making it RNG based again, I'd rather not bet my Honour Mode game on chance.
