What is it that I love? One of the big things you touched on actually, I love the healing. Healers in FFXIV are so powerful that they are rife with opportunities to contribute DPS, which creates a very satisfying dynamic, especially at higher levels when DPS'ing becomes a careful measurement of timing and risk taking. I love the world's aesthetic, expressive characters, witty dialogue, and my friends.

You've yet to experience all of ARR, so you may consider holding off on Heavensward. There is a lot of story at level 50, and several dungeons, and you've only experienced one class at a higher level, where classes tend to flesh out their full kits and handle better in the 2.5 second GCD. Heavensward will still be there if you decide to invest in it, but there are certainly more options for you in this game if you want to try them.