I'd rather avoid any 1-2-3 combo, it's better to look at casters for inspiration rather than tanks and melees. If I want more DPS options on healers, I'd rather have:

Gauges to build and spend (stacks or a 0-100 gauge, as long as I can build > spend)
Procs
Extra cooldowns
Extra debuffs to maintain (alongside the DoT)
Buffs to upkeep
Interactivity between all these (A proc reduces a cooldown by 5s, the debuff gives bonus gauge for keeping it up, the buff unlocks another spell, etc.)

A healer only needs about 4 or 5 spells in single target to make something regularly engaging, and an oGCD or two that interacts with those 4-5 spells. The only healer that should have a 1-2-3 combo is one that takes a page out of RDM's book and has an occasional melee phase (Sage could be this with Phlegma, but I'd rather a potential 5th one do this).