I see where you are coming from, in DOS1 we had saving throws much like pen and paper where they could just shrug off hard CC left it open to RNG. Now in DOS2 we have that RNG removed but you have to either widdle down their defense or target a different hard CC against their weak defense. (Knockdown for no phys armor, Freeze for no Mag armor). We have more reliable CC now but we do have to be smarter about it.
I am not positive that making you have to repeat hard cc 2-3 times just to actually stun them is a good solution. Many of these spells have decent cooldowns. As for consumables I definitely can see having to use 2 of them being a worthwhile change because my hunter with a quiver that would make green arrow jealous can counter just about anything. First frost arrow chills/slows them second one freezes. First knockdown hobbles second one knocks down etc..
I do agree though that there is too much hard CC and some of these encounters are designed based on you completely locking down certain enemies. I think a good compromise would be a tuning pass where some of these hard CCs are changed to soft CCs with the debuffs you mentioned. And that the actual hard CC be made fewer and more expensive on both AP and memory slots.
