I'm not sure if Perseverance works with every hard cc, I think it works with 2 magical hard cc and 2 physical, not sure if those are all possible. And yes it gives 5% per point. My main issue is, it works only in those specific cases: all armor gone and hard cc, so only if the fight goes kind of bad. If you are fighting well and never get cc'd the points put into perseverance are just wasted. Prolonging the fight because you have lower damage. Pain reflection at least works always, so it always gives you a gain. Also if Perseverance triggers it means you most likely lost 1 or 2 turns because of the hard cc.
Also you need to level it early to get it high enough fast, but in the early game you have hardly any armor and therefore it is even more useless.
Regarding the other stuff the issue remains: to cc first remains the core mechanic, the just removed the RNG and made it more grindy, because you have to deplete the armor first. Also the made teamwork of magic and physical users much harder, because both sides have to deplete their kind of armor first. Going either full physical team or full magical team are therefore kind of forced mechanics.
For me and my friend the armor system also kind of removed a huge amount of excitement. if you succeeded a role you were happy, if you failed you were not and needed to go for a different plan. You also needed to check you enemies, to figure out who would react better for which kind of cc. Now it feels more like a puzzle and not a battle.
Also increasing Body Building and Willpower gave you a better feeling of your hero getting stronger, because he was harder to knock out. Now he is just a growing onion. Also Glasscannon got kind of unusable, before all with the new AI.
The lesser feeling for growth of character also partly caused by the new AP system. And this new system also made skills like Adrenalin to strong? The just changed to much, I feel: The grapics are the same and the skills themselves are pretty much the same, but everything else is totally different now. (except some skills are now only usable with source points)