OP here. I'm glad to see this discussion turning in a more constructive direction.

The way I see it, every expansion is going to bring new abilities to jobs. So you have four options:

1. Just add new ones
2. Upgrade existing ones, like Air Anchor and High Jump
3. Cut old ones to make room
4. Allow choice

Square has been doing 1, 2, and 3. Maybe they can do that forever, maybe not. 3 has caused a lot of bad feelings, like BRD losing Foe Requiem. 2 isn't very exciting in most cases. And 1 is unsustainable.

So maybe at some point they can give 4 a shot. The way I imagine it, it would be like the old cross-class UI (that is still used for crafting/gathering), except you'd only have skills from your own job.

As an example, say you have three slots to choose, but six skills. So for NIN in 6.0, you could choose three out of Trick Attack, Ten Chi Jin, Assassinate, Mesui, and a couple of new skills. It doesn't have to get more complicated than that.

That would allow players a little bit of agency in how the job feels and plays. Obviously the skills would have to be balanced within a certain percent to avoid useless "noob traps" and TA would have to be balanced to come out ahead in a group but behind when solo.

Yes, hardcore raiding groups are going to require the optimal build and that's OK. The rest of us could just use the skills we enjoy.