Please stop simplifying and homogenizing the game. Please.

[Absurdity]

I always do wonder what the game would be like if they stuck to the ARR method of cross-job skills. Such as how if you wanted Swiftcast, you would level a Thaumaturge to level 26 at least.

Some existing examples are

Blood for Blood: For 20s, you deal 15% more damage and take 10% more damage. 80s cd. Requires leveling Lancer to 30.
Internal Release: For 15s, your criticial hit rate is increased by 30%. 60s cd. Requires leveling Pugilist to level 10.
Raging Strikes: For 20s, you deal 15% more damage. 120s cd. Requires leveling Archer to 4.
Eye for an Eye: Target a member or pet. For 20s, whenever that target is struck, there is a 20% chance the striker will deal 10% less damage for 10s. 180s cd. Requires leveling Arcanist to 34.

Then just apply Dark Knight, Astrologian, Machinist, Samurai, Red Mage, Gunbreaker, Dancer, Sage, and Reaper for what spells and abilities they have that could be cross-job with other jobs.

In ARR it was a bit of a chore but with how fast you go through those levels to unlock said crossclass skills nowadays you could finish it in an afternoon.