My group has been dabbling in some more narrative-focused games. Schema is the latest, and it's been great. Like most PbTA-style games, Schema does away with binary success/failure. It's a lot more nuanced than what I've seen in other games, though. Rather than just switching to a ternary (a bad outcome, a good outcome, a bit of both), each roll has a set of "stakes." The stakes are either good or bad things with eight flavors - so there are dangers like "delay" and "injury" and benefits like "efficacy" and "subtlety." The players get a pool of FUDGE dice, and use plusses to buy benefits and minuses to cancel dangers. It does several things that I really like:

1. It gives a little bit of structure and inspiration for the GM. Thinking about what happens on a partial success is sometimes a challenge. While you still have all the flexibility in this system (you get to decide what the dangers mean), it does help a little to have a framework.
2. Results get really complicated - the binary framework isn't just modified, it's done away with. There are whole arrays of outcomes and it creates interesting situations.
3. Players have a little bit of strategy. They get to choose a "bold" or "cautious" stance which gives some re-rolls. It's a very well executed mechanic.
4. There's virutally no math. No modifiers to add and subtract. It's super quick for resolution.

It's super lightweight in terms of rules and character creation, which is great for my group. It just took one quick example and the whole group easily understood all the rules they needed. Givien how easy it was to pick up and how narratively strong it is, it's a fantastic game for my group.