Anytime a job gets support utility, all other jobs of that role will get equivalents anyway (because balance), so this wouldn't really do much to give WHM it's own identity. Bard and Machinist are a good example, since a huge amount of their skillset is functionally identical (MP Regen, TP Regen, Defensive Buff, Vuln up debuff). It's pretty clear with healers once you think about it too; they all have Proshell and Graniteskin, they all have a 'support bubble', they all have an AoE regen and they all have a healing potency up cooldown. The differences between them are more gimmicky than anything else, and ultimately any support utility they would add to White Mage wouldn't be unique to it at all