You know which expansion was actually made for everyone? Stormblood.
For content, dungeons were still simple back then, alliance raids were a little bit harder, normal raids were decent, savage had some difficult floors, and they introduced ultimate for the first time. Also there's eureka for the people who enjoyed that.
Then the jobs, all of them had a skill ceiling, all of them had something to strive for. We also had a nice spectrum of difficulty from RDM to MCH.
That's a game made to include everyone, not whatever we're getting in DT, which looks like EW 2.0.