Let me elaborate:
In the context of FFXIV's current encounter design...
No one has ever accused WHM of being the bestest of "pure" healers, nor has anyone accused of SGE of being the bestest "barrier" healer. On the other hand, people have accused WHM of lacking in barriers, and SGE of putting out too much regens/HP.
Take SGE, delete Kardia, rename (Pan)Haima as Regenerative Stoneskin/Protect (or whatever
, I'm bad at names), smoosh what's left into current WHM, and... I think that might make for a reasonable jack-of-all-trades-master-of-none healer.
And
that, I think, is perfectly fitting for a healer that you can pick up at Lv.1 and take through the MSQ and Be Viable in Content(tm), while being in keeping with previous Final Fantasy games where the
only healer was... a white mage
(or close derivative).