A - is not a problem but a good thing. RNG in CC is bullshit and should never come back
B - Thats what armor is for
'RNG CC' while far from ideal, is infinitely better than the current system. Risk management is a big part of what makes P&P RPG's work, and those are the primary inspiration for Divinity.
Being made to take uncertain risks on receiving/failing a CC makes for a much wider variety of combat scenarios.
Armor being for protection is one thing, but once again it is far more interesting to have to manage healing and restoring armors at the same time, than it is to do one after the other.
Having armor offer diminishing protection also means it's much easier to give high amounts of it to characters that are meant to resist CC very well(tanks, bosses), as it means those characters can still be killed without stripping that resistance before hand, AKA preventing the from just chain CC'ing them, without giving them explicit immunities to everything(which is a much more elegant design, since it puts all combatants on equal footing rules-wise).
P&P RPGs ( DnD atleast ) have encounter/daylie powers for strong CC.
A better approach to armor and CC would be to give bosses or boss mobs more skills to increase armor or to remove CC. Your idea would just allow us to CC bosses with attack 1 while the binary approach helps bosses to actually do something.
A non binary approach would also nerf no dmg CC spells because they would mostly work on tanks.
Someone with just 1 max armor would loose it all with the first attack but you could easily "repair" the armor back to 100% -> CC immunity again. While tanks would maybe loose half and you can only repair 25% -> tanks is not CC immun.
The balance with non binary CC is horrible too.
Should the encounter be balanced for CC hitting or for CC not hitting or maybe half the CC hits?
If all CC has to hit you are fucked if it doesnt. If you dont need CC ( or just a very small amount ) the encounter becomes too easy.
Adding to that most CC is multihit in OS. A stuncloud checks whether you get CCed or not when created and at every move you take -> non binary approach ( OS1 ) it always works -> the reason CC was so goddamn overpowered.
Did a charm work first try ( or first round ) in OS1 on a very strong enemy -> enemies are fucked because the high damage high CD skills will be used on their teammates.
Right now we will always take the first round of damage and round 1 is the hardest hitting one.
