The armor system got implemented because some people seem to have moaned about the RNG of effects on the first game. Instead of refining the system with a less harsh fail or success version, they scrapped the whole system and invented a totally new and in my eyes pretty lacking new system. The kind of put in the new system to prevent perma-cc battles, but in the end they made it more tedious to cc enemies, but much easier to keep them in perma-cc as soon as you got their armor down.
Though there have been already tons of topics regarding this topic and also the pretty insane level scaling and dependence on getting good enough equipment. Though in my eyes those problems are only the tip of the iceberg.
