Looking at it currently we'll only be able to choose five role abilities, so here's the problem; of the ten, eight of them are routinely useful.
Cleric Stance: Now a mini-raging strikes for healers, 5% damage up for 15 seconds with 90 second cooldown. Not great, but decent. At least I think it's decent? Honestly that's pretty weak.
Break: 50 potency, 2.5 second cast, adds +40% heavy. Usually worthless, only required in very rare situations where a healer might need to kite, and can also be used by caster DPS (includes RDM). Very low priority.
Protect: It's Protect! You always want someone with this. The only saving grace is you can rock-paper-scissors with your raid healing partner and make one of you the protect-slave so the other can free a slot, but otherwise you want it.
Esuna: The absolute worst choice for a role ability since every class already had this ability under one name or other. Almost mandatory for all healers unless the game suddenly drops bad status, so they basically just reduced the number of role-buy skills to four unless you like swapping selections in between fights (and no one likes that!).
Lucid Dreaming: Useful. WHM and AST rely on it, SCH will probably want it now, too, due to the Aetherize nerf. You will almost certainly want this in primal and raid encounters.
Swiftcast: Useful... but annoyingly so. Healers want it for swiftres in general. WHM and AST can use it for long-cast heals as well and it's just a really useful ability for clutch situations. SCH used to use it for Shadowflare since that was literally their only spell cast over 2.5 seconds other than res, but since that's no longer the case... It's just for res, though it's also really handy for fairy resummoning if it happens to die. I don't want ot give this one up.
Eye for an Eye: A nice buff to have, but... Is it worth the limited role slot? Can only be used by healers, as caster DPS can no longer get it (SMN included).
Largesse: Divine Seal. Pretty sure everyone is going to take this as a quality of life buff.
Surecast: Now buffed to make you ignore stun, knockback, and other interrupting mechanics while casting, which sounds really useful in certain situations (especially since it prevents knockback), but is most likely going to be something to swap in for specific encounters.
Rescue: No one is ever going to take this except to mess with people. We just don't have enough slots for it.
I honestly hate the idea of having to swap abilities dependent on the encounter, so help me out here. What's my priority? Esuna, Protect, Largesse are solid, will probably have to keep Swiftcast unless the meta changes. Not sure about the 5th; if Aetherize's reduction is as bad as feared then LD will probably trump Cleric, or maybe I'll drop Swiftcast just for self-hate, but I personally want it for fairy resummoning in case it dies. I also mourn Eye for an Eye, but it doesn't measure up all that great against the other options.
First world problems.