Disclaimer: For those that are feeling disappointed in development direction, the following is not meant to argue whether you are "correct" in your feelings or not. It's not up to me or anybody else to say what you should or should not want the game to do. It's just a counterpoint that I hope will be interesting.
One of the things that I think works against DF is that fortress mode, as it was originally implemented, is not (AFAICT) the game that Toady wants to write in the end. It's the game that he started with (because you have to start somewhere). So there are a lot of people who view DF as a sandbox combat simulator, because that's what he wrote first. From that perspective, a lot of the the things that are being developed now don't make any sense.
Adventure mode is even more susceptible to this issue because from the beginning the only thing you could sensibly do is wander around and kill random things. When you read the adventure threads in the forum, many of the most active contributors play it as more of a horror simulator than anything else -- what is the nastiest thing you can do in the game? The vast majority of experienced players who are trying to do something else, mod adventure mode *heavily*.
But when I read descriptions of the game that Toady wants to write -- from Toady himself -- what I understand is that he wants a game where you can explore a fantasy world. He wants that world to be rich in history and he wants the actions in the past to affect the state of the future. Fortress mode is one way of affecting the future, by constructing a site and influencing an area. Adventure mode is a way of interacting with the world on a more detailed level. Legends mode is a way of researching the past the way a scholar would.
DF needs all the components that Toady has written as well as more that he has not written in order to be complete. But the game he has written up to this point is *not* the game that he is building. I think this, more than anything else, is the source of the disappointment. People, excited by the game that already exists, want bugs fixed, new features and enhancements for that game. Toady is not interested because he's building a different game -- or at least that is my impression.
When I first started looking at DF, I was not particularly interested. It wasn't until I started to see a few let's plays that showed people integrating fortress mode with adventure mode and legends mode did I start to think, "Hey, this is a pretty cool game". I'll be the first one to say that legends mode is too difficult to use (even with an external tool). It's also not available when you are playing fortress mode or adventure mode. And in both modes, it's hugely disappointing that actions you do seem to have very little (if any) effect on the legends of the world.
The artifact arc is exciting to me because it gives you some reason to interact with the world. From a sandbox combat simulator perspective, it's meaningless apart from being a tool to incite wars. From a "let's wander the world thinking of horrible ways to kill things" point of view, it's doubly meaningless. But from the perspective of creating some kind of logic and setting for what I'm doing, it's an enormous step forward. You can finally see a map in fortress mode! You can finally have some kind of sensible diplomatic interactions with other civs (compared to some random elves coming from who-knows-where telling you that you've cut too many trees down -- or your outpost liason, also coming from who-knows-where, telling you that the world is the same as always). And finally, I'm hopeful that the ability for artifacts to move around and be tracked, will move us closer to a world that is not just about killing things in inventive and macabre ways. I'm hoping that it will provide more focus for being able to relate to the world and to think about interesting things to explore/do (as opposed to yet-another-mega-project, or spending hours wandering to the other side of the world to kill some random creature/bandit group that really isn't doing anything to the person who asked you to kill it).
Like I said, this is not to detract from how others want to play the game. It sucks when the game that you want to play is not the focus of development. Having said that, there are some (me at least) that are excited to see some of the really important building blocks go in for the game that we want to play.