I feel this crowd control (cc) status design is too binary. Either you are completely helpless either you have nothing. Plus the immunity system to balance it is unfair because you have no way to predict who is immune. And, it trumps logic : void dragon can be knocked down, but random demon can't?
In addition, there is currently no use for the softer cc such as cripple or weaken when you can just completely shut down the opposition with blind/knockdown/stun.
I think it would have been better if the odd for hard cc were halved while adding a softer cc in case of "glancing blow". 100% hard cc changed to 50% hard cc + 100% soft cc. Assuming 100% success rate, On 0-50 roll you got the soft cc, on 51-100, you get the hard cc. All immunities are removed except the one that would make sense (ie: can't blind a bat). Willpower and bodybuilding apply normally, so high willpower/bodybuilding monster would still be de facto "immune" to strong cc unless these defences are lowered.
Probably too complex, so maybe it's just better to reduce duration as you suggested.
This would be the perfect solution for status effects in a pc game and it is not too complex, because the pc keeps track of the mechanic and not a game master. It could look like this:
Stun (Willpower):
Stunned for 1 turn on a failed save and slowed for 1 turn on a successful save.
Knockdown (Bodybuilding):
Knocked down for 1 turn on a failed save and weakened for 1 turn on a successful save.
Freeze (Bodybuilding):
Freezed for 1 turn on a failed save and chilled (-25% water and fire resistance) for 1 turn on a successful save.
Petrify (Bodybuilding):
Pertrified for 1 turn on a failed save and slowed for 1 turn on a successful save.
Charm (Willpower):
Charmed for 1 turn on a failed save and frenzied (attacks nearest target (friend or foe)) for 1 turn on a successful save.
Blind (Bodybuilding):
Blinded for 1 turn on a failed save and staggered (halved sight range) for 1 turn on a successful save.
Mute (Willpower):
Muted for 1 turn on a failed save and dazed (the AP cost of a spell is increased by 50%) for 1 turn on a successful save.
