Goal: To target play for players who don't feel very creative, or the pressure to bring something creative into the game stresses them out. (ie, I had a player who I tried the Mountain Witch "you see a grave, it makes you sad, why?" and you should have seen the deer in headlights look I got back). At any rate, my nugget of an idea is to focus on this gaming audience. They like to role up characters, but without flags or keys; avoid anything that would pressure them creatively.
I'm guessing only three types of Bangs gets these types of players involved, happy and comfortable:
Ninja's attack, Mystery! and Thar be Gold off Yonder.
They are basic, apply across most character types.
Can you think of any others? Maybe, Injustice-- though I think Injustice would work better as a backstory mechanic rather than bang.
Now, I could spend hours in a d20 type setting working out back story and all that, but its just so boring.
So, I'm thinking of a set of Decks, cards.
At some point people can pull from the deck and then it could be a form of the above Bang types.
Then another deck would have motivations, NPC's or World elements. Injustice would fit in these other decks or deck. And then in some magical, Oracley sort of way (haven't quite figured it out yet) the GM ties it all together (whips up the backstory, sets the scene and play begins). Prepping 4e combat is easy and fast, so I don't see a reason for that to slow it down.
I was thinking of cross referencing the card played with Symbols, so the decks sort of interact with each other (sort of like Arkham Asylum board game--monsters and movement). Instant variability, even with a low number of cards.
The GM would make Campaign specific decks of cards. Players would have the option to be creative, but no pressure.
Cards could get introduced to the deck as game progresses. Players would have option to introduce cards, but again, no pressure.