Personally I don't think the quality of the writing in the Citadel DLC deviates much from the rest of the game. The tone does, but it's supposed to; they're on shore leave and having a party, it's not a setting we've seen these characters in.
Ultimately it's as canon as the rest of the optionally playable game, which is to say if you don't like how it plays out you can skip it in your playthroughs, and then it's not "canon" to your Shepard.
@DocTheGamer
"Personally I don't think the quality of the writing in the Citadel DLC deviates much from the rest of the game."
Eh... ME2 is all about how the Lazarus Project was about Shepard and only Shepard. In ME3, Miranda is all broken up about the thought of her initially wanting to install a chip in Shepard's head. It is mentioned through both games time and time again that the Illusive Man did not want to alter Shepard's personality in any way... And now it turns out there's a goddamn fully conscious CLONE, with no memories. Gimme a break. Won't even start on the forced "funny" dialogues and everybody being oblivious and straight up stupid towards Brooks.
Sure, ME3's writing had really annoying B-type movie moments compared to other games (e.g. Kai Leng's stupid plot armor), but nothing else gets to such a low point as this DLC.
But yes, as you say, after I get the achievements, Citadel gets a huge skip from me on any future playthrough.
