For a long time, one of the biggest turnoffs for me about this game has been the lack of job customization. I loved having the cross-class skills in the base game, even though every job pretty much had a standard setup for endgame, because it let me play the job the way I wanted to play to a small degree.

Now those are gone, but I think jobs would benefit greatly from some kind of customization. Let's walk through some examples:

NIN
Complaint: Job is too gimped on damage because of Trick Attack utility
Solution: Give us a choice between TA for group content or a new ability that increases our personal DPS when soloing

BRD
Complaint: Identity of the job was lost when the songs lost their group utility
Solution: Give us a choice between songs that provide utility and songs that provide personal damage

MCH
Complaint: High ping means the job is unplayable in certain regions
Solution: Make Overheat a talent and let players choose a different ability with less ping dependence

SCH
Complaint: SCH's identity as a more damage-focused healer has been lost
Solution: Allow players to spec into more damage-based abilities if they want to

SMN
Complaint: Egis feel useless now
Solution: Allow players to spec out of egis if they want to or allow them to spec into new spells that take more advantage of the egis if they like the egis

MNK
Complaint: Abilities like Tornado Kick, the new Six-Sided Star, and Riddle of Fire are unpopular with some players because they are situational or slow down the rotation
Solution: Make these abilities talents and let players opt in if they like them or choose a different style if they don't

They are many other examples.

Sure, high-end raiders will probably need to spec into the optimal talents, but for the rest of us, some job customization could solve just about every complaint that players have about jobs right now. The main problem with jobs (and I think most of them play just fine, but there's always room for improvement right?) is that we can't tweak them in any way to suit personal preference. This feels so weird to me in an MMO that we can't. It's been a staple of role-playing games, let alone MMOs, since their inception.

We shouldn't have to switch a job entirely because of ping depedence or some other controversial aspect. We should be able to tailor the job we love to suit our personal preference. I know this would take a lot of work for Square Enix to pull this off. My suggestion is to only make a new healer job for the next expansion and use the rest of the dev time to implement a basic talent system.