What should be the next tank job

[Sylvain]

That would be different. It was always a bit of a melee/caster hybrid before.

Maybe if the next expansion takes us to the Empire, a Magitek Knight.

I'M very sceptical about the Geomancer being a healer.
Not that it wouldn't fit the role, far from that. But as I just posted for the Bluemage,
Healers and Tanks have less job thus the job identity must be very strong and unique.
WHM : Holy/Nature
SCH: "pet/fairies" "math?"
AST: Space, Star, buff

Geomancer would just get too close to the WHM imo.
On the other hand, there is only 3 caster dps and there is definitely room for some sort of "white mage dps" a bit like the elemental shaman in WoW.
However, my dream dps job would be the Time Mage, using a lot of arcane and time magic to damage. grayish, purple-ish and blakc spells.