Df is a materialist simulation. Even down to the individual thoughts of dwarves, there are values for every attribute present in the universe. I think this fact is why many comparisons to other media fail. DF is essentially a combination of the imagined fantasys of the 70's and 80's (which were themselves filtered interpretations of LOTR-esque fantasy of the early 20th century, which were themselves filtered interpretations of the oral traditions of Germanic people) filtered through a brilliant and mathematical mind.
DF is a product of its time, in that glorious early-2000's era of accessible consumer electronics, and specifically affordable CPUs. For DF would not exist if not for the audience's ability to play it! And I would argue this depth of simulation would not exist (in a consumer-facing sense) if the idea for DF had come about two decades earlier.
DF is tough to talk about now. It almost feels like its heyday came and went with the early 2010's, when it became a part of the internet's meme culture through boatmurdered and 4chan /v/, and other forums. That was the time I remember the forums most active, with all kinds of modded dreams appearing. Now, even beyond the walls of Bay12, the excitement surrounding DF seems to be waning. Ultimately, though, I think there are a huge number of fans, just very little to talk about at the moment between updates. That's how this game has always worked - lulls, and then flashes of community excitement.
I think you made an interesting point about how, nowadays, this older style of goblins, elves, etc is kind of passe. Or extremely passe, depending on who you talk to. I would agree that the things DF has become known for, like the strange bugs or the hyper-violence or the strange machinations of the A.I., almost came about accidentally through Tarn's attempt to simulate his interpreted fantasy. The quirks are there, but more interesting are all the ways these oddities interact. And that is entirely thanks to the dedication to simulation present in the dev.
So, fantasy made real via the digital, with all the associated philosophical implications. . I don't think this perspective is explored enough in our community.
Finally, to make some really broad claims, DF will ultimately become a well-known platform for fantasy modification. Which it already is. But with Steam and (hopefully) changes to the raw format of data, and the opening of more of the source code, DF really lays the foundations for all kinds of wonderful storytelling. IMO modification of DF is like creating your own story generator; you pick the actors, you change the attributes of the world, then you hit play. So anything to make this process easier will only further the beauty that is DF.
And, if not, if DF slowly tumbles into obscurity, it has already inspired hundreds of other game devs to focus on simulation and depth. Regardless of the present veneer of elves and gobbos, there is a ridiculous powerful engine under the hood, so to speak, ready for exploitation by countless creatives. And that's something lovely, no?