Return of Reckoning

You picked a small excerpt from nocturnalguest's post and ignored the part where he addresses your answer.

Anyway, something not yet mentioned here is the way healers do support: both dok and zealot buffing is passive or mostly passive - covenants, runes, others. AM/shammy is mostly the same, however both have some active utility to use - puddles, blinding light, gork sez stop, which make them more interactive than other classes outside of healing. Other than that every healer class has a way of countering other healers with CCs but especially in case of runepriests you'll rarely have time to do anything other than healing for all of those classes.

Kotbs/Chosen+RP/Zealot+Choppa/Slayer+Shaman/AM are easiest classes to play no extra mechanics.

BG/IB+WL+Sorc/BW+WH/WE+Engineer/Magus Slightly harder still easy to play, note BG/IB is harder beacause bloated kit, they have more skills and keybinds compared to other classes, other have pet management or combo points etc.

BO/SM+WP/DoK moderate you cant keep spamming abilities as you go, they have extra mechanics or resources to use abilities adding difficulty compared to other classes.

Marauder/SH/SW hard because stance dance requirement

Disclaimer: Overall the game itself is easy to play difficulty stated in this post is purely compared to itself and its made considering core mechanics/gameplay