Should healers be designed like tanks?

[Jovakim]

All healers can basically ignore their GCD heals and heal most content with just oGCDs already.

Aaaand that makes them more similar to what? To tanks, of course. The only thing that's different at this point is the lack of dps buttons and too many superfluous GCD heals.

The few times that you do need GCD heals, it gives you an opportunity to optimize.

W-what? I really don't understand what you meant by that.
Damage is king in this game. It doesn't matter what you do, if you're stopping your dps to do anything else, you're throwing optimization out in the trash. Sure, letting people die avoidable deaths is less then optimal, but as long as you can do it while not losing dps, you're optimizing.

Healers would need so many powerful oGCDs to be able to heal in prog and world first. It would make the role that is already easy even easier.

As I said in my previous comment, it's not necessary to throw away every GCD heal. They'll be there as long as there are mechanics that let you keep some of them dps neutral.

Just look at PLD. They have Clemency, and most (decent) players try to avoid using it if they can help it. When things are going smoothly, they don't need to use it at all, but when things go badly they have that one tool that can save a run. The exact same goes for healers.
Do we need more proof that tanks and healers aren't (and shouldn't be) that different?
Edit: Disregard this bit, I didn't explain what I wanted to say, at all.

Imagine an honest-to-God heal check: the party wipes if the healer doesn't cast a heal, and lives and clears if they do cast. Calling that heal "damage negative" is absurd. Clearing means you dealt more total damage than when you wiped.

You might not like it, but that's just what it is. Also, clearing =/= optimizing a clear. Keeping an optimized run is saving everyone from said heal check only using your oGCDs or one of the very few dps neutral CGD heals that exists.

Necessary heals are indirect contributors to DPS rate and total damage delivered.

Yes, of course. But wouldn't it be doubly better if you could get rewarded for that time you spent healing, by doing more damage afterward? Or to just keep dpsing and healing at the same time (oGCDs)?

You honestly act like we want to throw away all healing skills from the game. That's not it chief.

To arrive at a different design, you'd necessarily have to recalibrate how damage goes out in combat and recalibrate the minimal skill level required to clear content.

Not at all. Big overhauls to encounters are not necessary. The blueprint for dps neutral heals (Lillies) is already there. And oGCD heals are already plentiful.
After dps neutral heals are done, all the devs need to do is add more damage skills to fill the massive void that healing downtime is.