I would like it if they added in some of the newer effects or make new ones that would fit for the jobs when they do update them such as:
Murgleis: Occ. maximizes magic accuracy (maybe even 100% to make it not completely lol), enfeebling/enhancing magic +++, augments enspells
Laevateinn: Occ. negates elemental magic MP cost, all elemental affinity: damage +X, elemental magic skill +++
Nirvana: Augments avatars, negates perp. MP cost., summoning magic skill +++
Tupsimati: Auto-Iridescence I-V (built in weather obi and increasing benefits from weather), Weather: Occ. ignores magic evasion/defense/mdt

While over the top, we've seen the potential jump DD jobs can expect, so hopefully mages can expect the same. Of course, I'm keeping expectations low and only expecting an increase to dmg/matk/macc sadly.

(Also, while not mage-related, wouldn't mind seeing Nagi get Silent blow+++ to also give it something unique/powerful)