Why can't we have jobs with this level of depth and customization in FFXIV?

[Gilthas]

Even in FFXI there was customization but realistically if you wanted a good group you had only a set amount of choices per job.

Sure, but people see that mages had a huge spell list and that melees could equip a variety of weapon types and go "FFXI had so much more depth!".

For that particular example, it's not the rotation, it's the setup and configuration possibilities.

Like I already mentioned: Puppetmaster (or any job really) having a lot of setup and configuration possibilities is completely meaningless when only a very select few were viable. Puppetmaster didn't even have a viable endgame build. It was just a novelty job that was never taken seriously.