First off all i think there is a need now, to allow us to do more leves.
The reason is simple. After patch 1.18 leves are all about speed. So you finish one leve in 3-5min, if you want to play efficient.
That is what I am doing, and at this rate i finish my 8 leves in 45min.

The first step could be to reduce the gil reward and the waiting timer from 36h to 24h. So we can do our (now) shorter leves every day.

Another issue, which is more important for me is, that at the moment this leve system is designed for leveling one job at the time, but the game demands a "horizontal" progression and cross class skills.
Now you need to do all the leves with one class to progress at a good rate.
Leveling 2 or 3 classes at the same time is impossible, because you can do only 3 leves every 36h with one class.

I would like a system where the leves are limited for the class and not the character. This would motivate players to play different classes, which is a pillar of FFXIV philosophy.

So my idea of the perfect leve system would look like.

-Reset timer 24h.
-5-6 leve limit per class.
-reducedet gil
-reduced faction points

So you can play one class 30-60min a day.
People with a lot of time, can progress with 2-3 classes, instead of progressing with one class 2-3 times faster. So basically what they intended with fatigue.

Also: People who want to play all day, still need to grind, if they want the additional progress for their class.

The perfect system in my opinion.