But the game already does have a method to opt-out of certain duties, at least once you're at the point of repeating them. While most of them do have to be run once when you're going through that portion of the storyline yourself, you don't have to repeat them again unless you want to. What's more, it's an incredibly simple and obvious way to opt-out of them, since all you need to do is refrain from opting in.
You're trying to claim here that after you yourself willingly chose to tell the game, "Hey, I want to run Thousand Maws of Toto-Rak now, so find me a group to run it with," that the game is forcing you into that dungeon. It only puts you into dungeons you asked for. If you don't want it, all you have to do is don't ask for it. Don't queue for dungeons you don't want to run. Just check off all the dungeons you actually do enjoy and click the "Join" button, and DF will find you one of those instead.
