there's already some promising signs that dawntrail will be a better expansion content wise than endwalker, there's talk about thing doing a new large scale battle zone like bozja and eureka and mention that they'll be doing a new type of battle content.
We'll have to wait to see how it pans out of course but i'm cautiously optimistic right now. If they're keeping variant dungeons on top of that, this could even surpass shadowbringers in terms of content.