you have well over 480 item sets of which at least 400 are 5-piece sets. Introducing class sets which won't give new mechanics will just make another dozen of old sets not viable anymore. The only set which adds a new interesting play style and thus qualifies as a new set is the necro set (Nobility in Decay) and it is by far the weakest. It qualifies for a 3-piece bonus at best and probably should be a class-mythic.
Sets for the other classes are just generic buff sets which make older sets irrelevant...
I advise to drop the thought of class sets until you have interesting ideas for all classes. Meanwhile you could use the time to revisit old/unused sets and make a polished "perfected" version of them to drop in the Archive.
Perfected Galerions Revenge
(2 items) Adds 657 Critical Chance
(3 items) Gain minor Slayer at all times.
(4 items) Adds 129 Weapon and Spell Damage
(5 items) Adds 129 Magicka Recovery. When you deal damage with a Light, Heavy Attack, or weapon passive, you put a Mark of Revenge on the enemy for 15 seconds. After stacking 5 Marks of Revenge on an enemy they detonate for 1462 Magic Damage. You can only apply a stack once every half second and the damage scales off the higher of your Weapon or Spell Damage.