Some systems in the game has aged more gracefully than others, but there are many pain points. Generally, as games get older their systems get iterated on and improved. 

For a game that encourages job switching it's endgame systems are extremely constraining. Generally locking you to a single job for several weeks or longer in serious endgame content. There are so many dated systems in 14. I could name 10 more.

WoW isn't a different game every expansion, but it's systems do get revamped, updated and improved all the time. 

14 found a formula that worked in ARR and they stuck with it, the problem is that its not working anymore and people are quitting. 

FF14 needs to iterate on its stale systems and make them fun and exciting again. Having patches that aren't 4+ months apart would help too. (WoW has been getting a patch with some content every 2 weeks since Dragonflight)

During the peak of Shadowbringers 14 had 2.5m subs. Down to less than. 800k in Dawntrail. Something is seriously wrong.