Increasing the amount of cross skills really would not address anything, infact it'd just make the intial problem worse; there's no job identity, there's button bloating and skills feel homogenized. It'd be a much better alternative to get rid of cross skilling in general and bake in those "required" abilties into the moveset; WAR and DRK would have their own form of provoke that acts as their own skill rather than being derived from PLD. DPS classes would have their own way of managing TP (such as how much has purification) rather than everyone using invigorate, etc etc.