I feel like they could do this.
Pure healer + support
Pure healer + damage
Shield + damage
Shield + heal

This king of gives you all the play styles
Want to be a healer who blows things up- whm
Want to be a healer who focused solely on support - Astro
Want a healer who uses barriers and their damage heals with the barrier - sage
Want to protect allies from damage while providing boost to their defense and dps -scholar

This seems easy to balance to me