MP management is only fun if it creates decision-making. FFXIV doesn't have meaningful choices in its class kits. Your choice is you cast the spell you need to cast, or you don't. There's no lower MP equivalent of Glare. The best you get is Cure vs Cure 2. "MP management" in XIV, as kits have previously and are currently designed, would lead to actual /dance emoting in between casts instead of rolling your GCD. Hectic, unpredictable encounters aren't a thing in this game because the community raises Caine every time story combat becomes more difficult than a 4 CPM Curebot can handle. The game's GCD length also makes hectic healing less possible than it is in games where you can react faster. Not *im*possible, but less possible.
Your DPS buttons would be the first to go? Why? You have like three of them, in a kit overbloated with 20+ redundant healing spells. I'd gut the heck out of the healing kit long before I touched damage. Healing on a Blue Mage is more fun than healing on an actual green job, and Blue Mage has the opposite approach to a healing kit. It's mostly damage spells, with a great balance of healing staples that provide some actual choice. White Wind is a great oh shit button, but costs a ton of MP. Angel's Snack heals for a lot, but is on a long cooldown. Exuviation is great for the cleanse, but has a tiny radius. Stotram is an excellent balance of range, MP cost, and healing amount, but maybe it's not enough to survive the next hit. And then you get to have an actual rotation to execute when you're not making those decisions. I'm not surprised people find dealing damage on healers boring. It's pressing one button over and over and over and over again. Which is boring. Maybe they should do something about that.
I have literally never played an RPG where my healers spent the majority of their time healing. Buffing and debuffing is more arguable than that. Heal spamming usually only comes up in some specific, high-difficulty fights, and only during certain parts of it. In nearly all other content, there's a better use of action economy than blowing resources on making sure everyone's papercuts are immediately bandaged.