Would Discipline Priest Mechanics work in FFXIV?

[MistakeNot]

I doubt a melee healer would have absolutely all its healing locked behind it.

Probably not all of it, but the majority.
What I think of when I hear "melee healer" is something like the Bear Shaman from Age of Conan, or the (blue-line traited) Captain from Lord of the Rings Online. Both of them have major healing abilities that require hitting opponents in melee to trigger. They have some lesser healing abilities that can be used even outside melee, but they are quite limited outside of melee.
They also happen to be my favourite classes in those games, so I certainly would welcome a melee healer class in FFXIV as well.