While I enjoyed them to an extent and honestly wish this game had a subjob adjacent system like FFXI to improve customization of play, you will never see cross class skills return. In a game like this, they aren't optional. Cross class skills were mandatory, if you didn't have them people didn't bring you for high end content. This resulted in heavy complaining and they were removed and replaced with role abilities.

It's a flaw with the design of the game really. Cross class skills were poorly implemented. I'd love to see them take another crack at something like it, ideally with more customization like subjobs offer in XI as I said, but SE seems to want to take player choice away rather than give us more unfortunately. We don't even have talent trees which is a VERY basic MMO feature almost every game has except this one. They design jobs to be played one way and one way only with zero actual thought or choice on the part of the player.