That's one of the things I'd like in a system: "players can make plans and tell whether or not they're likely to work". The +tb+ system required a lot of GM calls early on, but after a while the butterflies were spell-casting a lot with a high confidence that the character actions were reasonable, which was part of what I enjoyed about the game.

I keep thinking about Dominion and how almost every rules question I've had was resolved (a) in their card interactions and (b) in a consistent way that was what I'd expect from reading the exact card text. I want an RPG that's like that: abilities interact in complex, interesting ways that are still completely predictable. n.n