This is a 9 year old MMO soon. The game needs to evolve and keep things fresh to maintain momentum and growth. ARR through to Shadowbringers all felt unique in their own way.
ARR was a rebirth as it's name suggests
Heavenward was almost as thorough a rework as ARR in terms of gameplay.
Stormblood was a comparatively weak expansion in some regards but even so it still ushered in many significant rethinks not only of classes but also the importance of side content such as Eureka.
Shadowbringers brought with it a new found focus on accessibility and narrative.
Endwalker is pretty clearly aimed at riding the coattails of Shadowbringers huge success but as a result, it lacks it's own identity as an expansion. It's just doubling down on the same highlights as Shadowbringers (And IMO falls short at doing so).
To give an example of what I mean, look at how a typical raider will tackle each new Expansion release.
Level a job through the MSQ > Spam Dungeons to get basic tome gear > Spam primals to get Primal Gear > Wait 2 weeks for Normal Mode Raids > Farm 2 weeks of tokens for Normal Gear > Buy/craft Crafted and Penta Meld it > Wait 2 weeks for Savage > etc
This routine has remained strangely intact from Heavensward through to Endwalker with the only change being the relative ease of materia now vs back then. I'm really not sure why.
There are plenty of other areas SE could throw curveballs at us again. Bozja's raids were a decent curveball, lets see more of that elsewhere to break how formulaic and by the numbers the core gameplay loop is in places.