I think this was EW content design problem in particular.
As many have said before, there's no "midcore" (or however you want to call it) content in EW. There's no large zone where players of different skill levels can gather and do something together. Bozja was great in that regard, some skirmishes, but especially CE used mechanics from the previous fights but made quite a few additions to them, so they are fresh and fun to do and do offer a higher difficulty. All 3 large scale raids i.e. CLL, DRN and Dalriada were very fun on content.
Usually Alliance Raids are harder than regular Dungeons and Trials content (YoshiP himself mentioned that they design Alliance Raid with harder and less noticeable mechanics so even if more casual players make mistakes, better players can still carry them), but the devs overcorrected after Nier complaints way too hard. Bosses have no health and spend way too much time tutorializing before they start mixing mechanics in a half-interesting way, by which point they are dead. Bosses spend way too much time telegraphing one attack. Thaleia is very guilty of this.
EW Extremes were somewhat on a weaker side with the exception of Barbs or Golby.