Here's a few things that I thought of, mostly focusing on SMN and SCH, because those are what I play most.

Summoner:
lv 55: Leviathan Egi (Summon IV) - summons support-type pet focused on buffing allies
lv 60: Ramuh Egi (Summon V) - summons support-type pet focused on debuffing enemies
I think the order or effects of these two could be swapped, but the general idea remains the same. Since Summoner seems to be pitched as a more utility or support-focused casting dps, it seems logical to add egis that are designed specifically for this. I would expect them to still have some amount of offensive capability, but would probably be less powerful than Garuda.

I would like to see a job adjustment so that the damage all the egis deal is based off the Summoner's INT, and then take advantage of this adjustment to trade SMN's high strength (compared to BLM/WHM) for higher piety to help resolve some of the current longevity issues.

Scholar:
lv 55: eruditio - heal potency 100; erects a shield for 8x hp recovered that may/may not stack with galvanize from aldoquium/succor
lv 60: radiosus - 5-15% damage reduction + HOT 100 potency; duration 30 seconds

Arcanist class abilities/traits:
lv 52: Enhanced bio: extend bio duration to 36 seconds
lv 54: Bio III - potency 35: duration 40 seconds -> bane and fester re-specked to include Bio III among spells relevant to their effects
lv 56: Mutating virus: immunity duration after the effects of virus reduced from 60 to 30 seconds
lv 58: Energy Siphon - potency 150: absorbs damage dealt as MP, consumes one aetherflow stack - basically an mp-focused energy drain
lv 60: Maim and Mend III - increase base damage/healing by >30% + Aetherdam III: allows stacking of 4 aetherflows