I don't think that it's all that hard.

Tanks need to mitigate. Healers need to heal. These are essential actions that you see in every job across a given role. These aren't going to be the basis of an identity, because everyone is going to be able to do them at some baseline level of competency in order to clear content (this is also why viability discussions are pointless). So talking about a "defensive tank" identity or a "pure healer" identity doesn't make a whole lot of sense.

Take SCH for a second. You have a pet who can help you multitask and do things for you, be it focus healing an ally, throwing out raidwide regens, and even buffing the group. If you manage your pet well, you can buy yourself time to dps without having to hardcast heals. That's a pretty neat identity.

Take SCH for a second. You have this Aetherflow resource that you can store up to access a variety of instant cast abilities, be it burst healing, raidwide shields, or even dps. If you manage Aetherflow well, you can buy yourself time to dps without having to hardcast heals. That's a pretty neat identity.

Take SCH for a second. You have access to a variety of powerful barrier shields absorb a flat amount of damage before they expire. They don't decay in potency over time, so if you have a lot of shields up and running on the group, you can buy yourself time to dps without having to hardcast heals. That's a pretty neat- you get the point. You can do this with WAR as well.

There's no reason to throw your hands in the air and say "Golly gee, we just can't come up with healer concepts," when you have five different healer identities packaged into a single job. And then the devs scratch their heads over why we end up running the same comps every single expansion. Go figure.

We've been staring at the solution for about four years now. You don't need to be a genius to figure it out. I'm just hoping that the addition of a fourth tank and healer will cue the devs into realising that it's really, really dumb to create a super versatile job at the expense of three others. You're not going to win over new tanks with media tour Fell Cleave highlights alone. Failing that, I'll either be pinning my hopes on a fifth tank and healer, or another Calamity. They'll get it eventually.