Honestly, I'd say it's totally viable in endgame. They said we're going to want a pure healer and barrier healer for endgame content, but the ONLY thing of importance regarding this is that barrier healers can apply AoE barriers for prog. There's no reason to take a pure healer based on this idea that the pure healer role has some kind of inherent advantage the barrier healer doesn't, so there's nothing wrong with a 2 barrier healer comp.
Just run AST/SGE or SGE/SGE and let WHM and SCH rot
