Think it be more simple for devs and players to focus on 1 class = 1 Job.
(Would change some actions on SMN & SCH around a bit and make new actions)
Can keep SCH class a pet class. Can make it Calculator or Tempest. As a lv1 Pet for the class... Caitsith? Caitsith being more of a Mini Tank in a way. Once Job is unlocked Fairy becomes more for healing but Caithsith still be useful later on. Acts like a weaker version of Titan Egi.

Actions

Action:Field of ______
Places a Floor AOE that players stand on to gain increased HP cap & healing overtime.
(3x size of Flaming Arrow)

Action:Calculate
Increases effects of healing & damage by you & your pet over period of time.

Spell: Aspir: Absorbs 50% of damage dealt & restores HP & MP

Spell: Barrier: Casts Different type of Protect & Shell on players

Spell: Dia (Remove Bio)

Spell: Dia II (Remove Bio II)

Spell: Physick (CAL/SCH mainly, optional to place it cross class action for ARN/SMN)

Spell: Resurrection (CAL/SCH mainly, optional to place it cross class action for ARN/SMN)