What I would like is SE finally adding sub/multi roles.
Just some brainstorming.
Sub Tank:
SAM Tank with Counter mechanics. Using it in the MT or yourself.
DRG Tank with Jump mechanics can give him a dodge up to x% of total damage.
MCH Tank using robots.
BLM Tank using Manaward and umbral stance to use MP as a tool to mitigate damage.
SMN Tank using Titan.
Sub Dps melee:
WAR Dps with burst and warcry buffs.
Sub Dps Ranged:
AST Dropping Ress to gain a combo that permits the upkeep of Lightspeed infinitely.
GNB Gains ability to transfer the vibration from the Gunblade as a wave through the air with all their actions, gaining speed with Combos and different bullets.
Sub Dps Caster:
WHM as Geomancer'ish
DRK The Dark mage. Consuming HP Shield to gain access to Dark Spells.
PLD The Holy mage. Uses melee actions to increase the power of the next spell.
Sub Healer:
RDM Dropping Jolt spells to get access to more cure. Using cure to restore both mana.
MNK Healing with stances, Fire for raw heal increase, Wind for skillspeed/spellspeed, Earth for shield, and the new one Water for regen.
NIN Healing with ninjutsu.
DNC Healing with the dance.
BRD Healing with songs.
TLDR:
Dps/Tank: SAM, DRG, PLD, GNB, WAR, DRK, MCH, BLM, SMN,
Dps/Healer: AST, WHM, RDM, MNK, NIN, DNC, BRD