The A Dance of Masks DLC for WotR adds two things to the main campaign.
The first is a somewhat sizable questline which triggers partway through Chapter V, which happens to include a mostly optional set of arena battles against an assortment of fairly random opponents. Apart from some awkward voice acting, as if the actors hadn’t had time to re-familiarize themselves with the roles (only Regil and to a lesser extent Woljif didn’t stand out), there’s nothing much on the technical side to complain about. Mechanically it’s pretty easy and tosses a bunch of overpowered items at you on top of that. That said, the arena fights on the other hand are a completely mixed bag. While most don’t pose much of an issue, there are some that are just plain ridiculous (like the wild hunt, or that shadow monk if you don’t have Mass Heal). I certainly do appreciate the free Greater Restoration after every match though and the rewards are useful enough.
The other addition is a new quest available to the Devil mythic path if the queen survives the events at Iz. Not really sure what the point of that was honestly as it feels kind of like it’s sectioned off into its own thing and doesn’t really flow well.
I played the above shortly after quickly running through the Gold Dragon endgame and finishing up my Aeon playthrough (made some mistakes there like going Crossblooded when the Abyss STR bonus gets overridden by DoM’s +4 attribute potion and forgetting Transformation) to finally get that Sadistic Game Design achievement.
Aeon’s unique ending is pretty good and the whole altering the past theme is integrated fairly well. Gold Dragon on the other hand is mostly just annoying, with its quests sending you out into the middle of nowhere, but it also has a somewhat unique ending which at least fits the theme. Devil, as it turns out, is even more annoying than Gold Dragon since you have to wait months to work through the event chain that grants Mythic Level 9… and it doesn’t even have a unique way to resolve the final battle.
Final thing to note is that I also cleared the full-power version of Sithhud added by importing a Lord of Nothing save. It is not something I ever wish to do again. The first two phases are fine, no problem. The third though… in the third you have to kill him nine times while he gets slightly stronger after each death and constantly jumps around the arena. I actually almost ran out of Empowered+Bolstered Hellfire Rays on Ember while taking him down.