I like the idea of letting players choose for themselves, have some sort of Healing Power stat that players put on their equipment, but then let them choose what equipment they want to put it on and what 2ndary stats they want.
In this way you could choose to put healing power on heavy armor and equip a shield/wand with hp as your 2ndary stat and become a very tanky healer. This build would make you nearly impossible to kill, but also means you do no damage, this means you will always need to be in a group, even for tasks most other classes find easy to solo.
Alternatively you could choose to play the more modern version of the cleric by putting healing power on cloth gear and equip a staff with int as your 2ndary stat. This would allow you to do moderate spell damage while healing, but would also make you a glass cannon who must avoid close encounters.
Lastly you could be a “battle monk” type class by simply putting your healing power on leather armor equiping a sword and using str as your 2ndary stat. This would be a more advanced build, perhaps better for soloing and less desirable in a group, one would need to strike a balance between healing and dps, plus being a more squishy close range dpser would pose its own challenges.