I was looking at some older games from the 1990s. I remember now when "Advantage/Disadvantage" systems were all the rage.
Now, when I say that, I don't mean it in the 5e sense where it refers to rolling twice the normal dice and taking the better/worse result. No, I mean "here is a list of good traits and a list of bad traits; you have to pick some from both." That is, of course, a gross simplification, but I think you get the idea. Often, you had an allotment of points and pick Disadvantages would allow you to get more Advantages.
I think you can make a clear line between their rise and fall from prominence to the rise and fall of Aspects/narrative descriptions+resource bonuses.
First, let's discuss why people like Adv/Dis. It's worth noting that D&D's class system always rubbed people the wrong way. It's a gamist concept that places stark limitations on characters for purely game design reasons.
We had seen quite a few deviations, but none of them had caught on for their own reasons. Skill training systems were too cumbersome in play (think Final Fantasy II or Elder Scrolls), Life Paths were popular but were hard to design and balance, etc.
Adv/Dis seemed like a simple, easy universal solution that could be plopped into a game without having to have the entire game built around it. Thus, it was adopted as a way of offering more customization to players.
Secondly, let's discuss why it fell out of favor. Adv/Dis breaks down once you start trying to balance the adv/dis. I don't feel like being exhaustive, but the issue tended to be the case that advantages didn't all have the same use cases, disadvantages would often become a game of finding ones easy to mitigate or that didn't have serious penalties, and some disadvantages actually being advantages (and, more rarely, vice versa).
I'll elaborate a bit. Even if Advantages all had the same mechanical benefit, if their use cases weren't the same then there could be inequity. Maybe they all give +2 bonuses, but if one can almost always apply and the other applies once in a blue moon then that's not balanced. Some disadvantages could be easily mitigated, like having a bad odor, so they are just free points. This was especially true if it required GM enforcement: putting the GM in an awkward situation of having to decide when to punish the player. Other disadvantages had penalties but they weren't serious. Perhaps nobles always look down on you. Well, in our military game, that won't be a big problem. Lastly, some disadvantages were actually advantages. Classic example is a nemesis. That sounds bad, but it means you get more screen time and get to be the focus of the story. That's actually a benefit.
As such, they stopped being the "IT" thing.
Thirdly, let's discuss what Aspects are. I'll define Aspects as an all-encompassing term for game mechanics that can be described as "a word/sentence that describes your character that gives you narrative advantage/disadvantage by being true and can provide mechanical advantage by expending a resource." Fate Core, Nobilis, Chuubo's, Cortex Prime, Fudge, and quite a few other games began using them in the 2000s. They are older, but they got more popular around this time.
Lastly, let's discuss how I think they are connected. Aspects came to prominence, in my mind, because they 1) seem to rectify some of the problems of adv/dis (even if they aren't perfect or the right feel for everyone) and 2) are easy to include with less work on the designer's part.
Adv/Dis are not all balanced? Well, often Aspects are typed (High Concept, Trouble, Relationship, etc) so they have clear use cases. They are also often made to be dual-sided: each one can be good and bad. You want that as an Aspect going against you often gives you more resources for later. Aspects main mechanical benefits are tied to the expenditure of a resource. That stops Aspects from being too useful or too useless: the real draw is the resource management. The mechanical effects are also uniform. In Fate Core, they allow you to introduce a story detail or add +2 to your roll. That's pretty common.
You essentially removed the issue with balance by making everything the same. They have assigned use cases, they push you to make each one double sided so you can get more resources, and their real benefits are tied to a finite resource that players often receive a uniform amount (and, if they don't, that's often to compensate for weaker characters). It is possible to make one Aspect apply too often, but, since that isn't hard corded into the book, it is less of a hassle to just ask the player to rewrite it. It's not like you need to homebrew a new ability.
Secondly, they are just easy to include. You don't need to make a long list of powers and drawbacks. Hell, Fate Core is on the creative commons with attribution. You absolutely can borrow their entire section with well written rules and guidance on making Aspects into your game. I won't like: I've done this multiple times. It's so easy and cuts a lot of time out of development while still giving players a flexible system to customize their characters.
It isn't hard then to see why Adv/Dis is rarer nowadays (it happens and Savage World is a strong torchbearer) and Aspects are...well, were, more common in the 2000s. It feels we moved on from them due to PbtA and FitD in the indie scene. In the main stream, classes have made a comeback due to 5e.
Still, for a time, Adv/Dis was very popular, it hit a peak, trailed off, and it feels like Aspects came and ate their lunch. Then, PbtA did and so on.
That's just my observation, anyway. What do you think? I'd love to hear it!
