I suppose I can't speak for others, but I agree that just going back to the way things were doesn't necessarily make healing more fun or engaging. What I do think, though, is that we do need to take a look at how the healers used to be on paper and really take to heart the things that people enjoyed that were ripped away--namely the Scholar's wider access to DPS tools, Selene's and Eos' individuality, and the AST's old card system and how the highs felt while using that system.
What we need to do from there is really think about how each healer approaches their responsibilities, which in Final Fantasy XIV are:
1. Obey boss mechanics and stay alive.
2. Keep the party alive through healing, mitigation, and survival utility
3. Manage their resources so that they can continue to keep the party alive
4. Deal as much DPS as possible either directly or through support
Right now, each healer approaches each of these responsibilities in the same way.
Boss mechanics will naturally be approached the same way as healers of course, but there can be something said about the lack of unique or demanding boss mechanics that target the healers in recent content. Remember Searing Wind from Ifrit EX? Briny Mirror from Leviathan EX? What about Shinryu EX's Dragon Heads? Why not start including adds that are invulnerable and heal the boss for 30 seconds, but can be put to sleep with Repose to negate that healing? What about adding Dispel as a role action and have bosses start applying dispel-able buffs to their damage output or defense that we as healers need to remove? We talk a lot about how there isn't enough damage going out and thus too much DPS uptime for healers, but we can also add more mechanics like these to fights to give us more to do other than just DPS and heal when needed.
What about keeping the party alive and DPSing? Right now, each healer approaches these in virtually the same way when played optimally: Your GCD is for DPS unless absolutely necessary and your OGCD is for healing so that you can continue to DPS with your GCD. Why don't we experiment with different ways to approach this? What about a healer who's GCD is for healing only and their OGCD is for DPS? They don't have a GCD Glare/Broil/Malefic, but OGCD sources of damage only? It's not like they'll ever be synched down to level 1, even if you enter the weakest FATES in the game, so you can balance them around having their damage by level 4 or 6 or something. Make a healer who throws GCD DPS onto their allies to deliver so they don't have to--a healer for the players that don't want to DPS directly and can instead use their GCDs to support the party.