I would add an ultimate weapons. One that you can start when you are really low level or would require you to go back and do content (normal-hard-savage) synced. Like get drops from fates in starter zones, low level dungeons and the like, even potd, hoh, hunts, primals, anything battle related (no crafting/gathering items). And have this weapon always be equal to BiS if you want to put the time in. Allowing us the extract a special materia from our soul stones to complete certain steps would also make those items just feel more important.

Just something that took time, something that was more rare but not a requirement, something that just didn't become a glamour item after an expansion came to a conclusion.

This would give many of us something to work on during slow times. This would also make that item more relevant and give us more of a sense of accomplishment. Goals, especially long term goals, are something this game is severely lacking. And installing something of this sort would be just a nice time sync for those of us who do not want to unsub between patches but have little else to work on.

This could also be applied to gear. Give us a job specific gear set that begins at say level 50, ilvl 90 and let us work on building it up to be equal to BiS gear.