I think it could be too overpowered maybe. WHM also has no kind of AoE shield (Temperance is a defense buff like the effect of Collective Unconscious), and AST already has Neutral Sect if you need shields.
Also, regens are usually more useful than shields anyway. I like that it's a free AoE regen, you rarely need Aspected Helios because of it (and vice versa in Nocturnal).