From a Tank's PoV...

Several people have mentioned Neron's Underworld, and that instance is the epitome of bad dungeon design, with all those small doorways, and enemies just inside waiting to pound you. Then all the friendly NPCs, robot sidekicks, Furies/Watchers/Guardians/Crystals/Bricks, block said doorways. And that's not counting summoned henchmen and sidekicks.

Now, maybe it's designed that way deliberately, to keep players from speedrunning to the next boss room. What it really does is ensure that one or two players zip through before the enemies can react, and the entire rest of the group gets stuck with the enemies -- until the first player reaches the boss room and teleports the rest of the group to them, along with the enemies they were fighting.

Another possibility is to let player characters be able to push pets/henchmen/sidekicks out of the way.

I'm not opposed, but as I said I'm really not fussed with players being able to phase, it's NPC's I don't want phasing, not only for strategical reasons but also because I just find the premise of a boss phasing through everything to be stupid, I actually feel the same for players as well but compromise on players because of how annoyed it seems to make some people.

As for things like the design of NU, what if I told you I thought they just picked an instance or environment they thought was cool and gave almost no thought to the impact on players with respect to navigating hallways. I could be wrong but I really think it was just a case of not thinking about it in that respect, but that's just me.

Just another step by Daybreak towards the massacre of this role, nothing surprising after all...

I actually believe that. I was giving them the benefit of the doubt, that it was structured that way on purpose.