There are several games on my “to play” list that I’ve not gotten to play, and some of these are because the other players weren’t interested. But I’ve usually not pushed the matter, either. And then there are the games that I don’t even propose because I know they won’t fly. I’m not even sure I’m interested in playing HōL or Burning Empires, so it doesn’t matter that my friends aren’t. (Not because they’re bad games, but because they’re just not my cuppa.)
But there is one game that I’ve repeatedly proposed and almost always had shot down: Aria. Once, I got people to play it for a bit, and Ogalepihcra was the result. But most people take one look at the rules and have no interest. In particular, the fact that you basically have to create not only your setting but the equivalent of races and classes* and even perhaps the skills they’re built out of is too daunting to many. Aria is a system designed to create worlds and tailor the rules to fit them. Instead of trying to fit the world you envision to a predetermined set of classes—or even skills—Aria believes that the rules should be tailored to the setting. And it does an excellent job of them.
Then there is the next obstacle: the dice rolling system. It’s well explained, but nonetheless one of the more complex I’ve run into, open-ended in a slightly odd way that gives a large range and a lot of possible results on every roll, while still only using a single d10. I think it’s a welcome trade-off of extra complexity for extra detail in the results, but I completely understand why others don’t.
And if you want magic in your setting, you’ll have to build it yourself—even moreso than the rest of the setting. The non-magical parts of the rules could be used on the fly, much like using just the core book of Hero System for your game, by just building each thing you need as you go. Not the magic.
I love the system—I think that, for what it gives you, the necessary effort is perfectly reasonable, even modest. And this is coming from someone who normally eschews any system that’s crunchier than Savage Worlds, so it’s not just that I like my games complex. But it is a lot more effort than most other games. And much of it is unavoidable effort—you can build a simple game with Fudge, but Aria is always detailed and at least somewhat complex.
*n.b.: Aria doesn’t use classes in the RPG sense. Characters are built up out of skills and access to skills, similar to a lifepath system like Traveller or Cyberpunk or Burning Wheel.