Gatekeeper Naglfahr is currently a pathetic boss encounter in the game.
His spawn position is really bad. He slowly jumps down in a corner and is completely vulnerable during that time. Which is the big reason why the boss encounter’s a total joke.
So I want to suggest what would be a difficulty buff/increase to the encounter in an interesting and hopefully fun way without it demanding much resources.
Let the gatekeeper spawn from behind one of the gates and charge players immediately as it opens. And on top of that, you could have two chaos warrior spawn at the beginning of the fight and during the gatekeeper’s transformation.
Edit: Also consider reducing the transformation time to like 3 or 4 seconds max.
Ideally I imagine the spawn points of the Gatekeeper would be random between one of the two gates and the chaos warriors could be randomized between the points shown in the image below.
I believe these changes would make the encounter much more dangerous than before but without making it under/overwhelming.
The encounter in it’s current state usually lasts between 10 and 40 seconds and there’s not really anything of interest going on because the gatekeeper starts out vulnerable and without anything to back him up.