I got two, Job design and character creator. The latter is self explanatory

-Bring back cross class so as to be a reward for levelling more than one job. There was nothing wrong with the system. It could have existed alongside role skills easily.
-eliminate role skills by making them standard additions to the relevant kits

-design each job to have a unique playstyle and identity within its role. Healers get redesigns to reflect gameplay of dpsing and healing with synergy between the two halves of the kit. Tanks likewise get rewarded for proper mitigation and enmity made better and more visible.
Raise overall job complexity back to SB levels at minimum. Preferably to HW levels.
Update hall of the novice and make it mandatory



Optional
-make a talent tree system with a pool of potency points.

The talent tree will take certain moves that have changed or been removed over time and additions to job kits and make them optional. For example Celestial opposition can have either its stun and time extension or its instant aspected benefic effect.
A dark knight might choose to have delirium 1.0 and scourge and get shut of dark mind and discount inner release
Then you have a potency pool- you can distribute this to your talent actions. This pool will go up or down with different actions so as to ensure some combinations of actions don't completely overshadow others.