These changes fix one of the main issues Inquisitors had before: too many different spell effects that you wanted to keep on your bar at any given time. Taunt, your two melee attacks, Magic Break, Mez and AoE stun. Rest of the slots were either Kick, Silence, Choke. Not a lot of wiggle room to slot in cast speed slow, mana burn, and whatever else.
If the mana scaling was changed to be not as harsh, then the class may very well be the best designed one in the current state of the game.