Confused about people's obsession with open world raids/dungeons.

[Lucifer]

Exactly. Open world content is needed, but it shouldn't be the way to obtain the best gear in the game.

As for open world content, I'm hoping for stuff like seiges, campains, etc. to help defend a city. Sorta like ToAU, but didn't suck as much as that did where you just waited for enemy forces in town.

There has to be some incentive to openly compete with other people to get a reward. This is why the gear SHOULD be better. Factor in the fact the monster might respawn once a day or once a week. This is gear for those willing to invest their time.
If the gear at the end is alluring to you but you don't want to go through the process of getting it, even though you KNOW you don't need the gear to complete any content in the game, the problem lies with you.