"Project Thornburg" (working title)
Threeforged #1599, Phase-1

The concept of this game is to encourage a wide variety of actions in a scene.  Characters really shine when they work together while playing to their own strengths.  This pitch assumes heroic fantasy, but the system is adaptable to any genre.

GM: A green gleam from the heart of the apparatus tells you that you have found the jade idol at last, here in Doctor Korzu's laboratory.  The door opposite opens and ten guards pour in, followed by the mad alchemist himself.  "Stop them!" shouts Korzu.  Guards rush forward, swords drawn.  What do you do?
The Old Way:
Frank the Fighter: I attack with my axe.
Thelma the Thief: I attack with a backstab.
Wanda the Wizard: I attack with a spell.
<Repeat until one side is dead>

Why should every character be equally effective in combat?  Think of the fight scene in Balin's Tomb, in the movie The Fellowship Of The Ring.  "They've got a cave troll."  Is every protagonist hacking at baddies?  No!  Samwise defends himself with his frying pan.  Frodo dodges around columns, just trying to keep himself (and the Ring) out of the cave troll's reach.  The great wizard Gandalf is reduced to fending off orcs with his sword.  Only the fighters rack up any sort of body count.  Later, Merry and Pippin leap onto the cave troll's back, doing little damage with their daggers, but enabling Legolas to shoot an arrow down its throat, killing it.

Each hero contributes according to their own abilities.  Some fight, some distract, some protect the McGuffin...  Different sorts of conflicts (physical, social, skill challenges) spotlight different heroes, while the others find ways (effective or comedic) to support the spotlighted characters (or pursue their own agenda…).
The Project-Thornburg Way:
Frank: I've got this!  I swing my axe wide, holding the charging guards at bay.
GM: You can hold off many of them, but some will eventually get past you.
Wanda: I stay behind Frank, looking harmless.
Thelma: I make for the jade idol!
GM: You're going to draw attacks from the guards…
Thelma: That's the idea!  I dodge around stools and under tables, keeping as many as I can busy.
Frank: Thanks!
GM: Okay, roll dice, you two.  Thelma, three thugs are occupied with trying to grab you.  You're keeping just out of their reach, for now, but they're backing you into a corner. Three guards go down under Frank's hewing blade, and he's holding off three more, but one gets behind him with murder in his eyes.
Wanda: I try to conjure a frozen puddle under the feet of that last one!
GM: Roll dice… success!  A sheet of ice appears at your command.  The guard slips and goes down hard.  He's out for a bit.  Meanwhile, Doctor Korzu is pulling levers on the infernal machine surrounding the jade idol.  Bits start rotating and bulbs glow.  It hums with magical power.
Wanda: Oh, I got THIS...

SAMPLE CHARACTERS:

Thelma (Burglar)
Strengths: Steal, Sneak, Break in/out
Talents: Eavesdrop, Acrobatics, Ambush, Conceal
Hang-Up: Doesn't trust elves.
Goal: Steal the jade idol.

1-3 Strengths.  3-5 Talents.
Strengths and Talents must be unique across all your characters.

Frank (Warrior)
Strengths: Fighting
Talents: Intimidation, Running, Feat of strength, Battlefield Tactics
Hang-Up: We will succeed as a team, or not at all.
Goal: Take over this caravan.

Players write their own Hang-Ups and Goals, working together to create interesting overlaps, and perhaps conflicts of interest.

Wanda (Wizard, Half-Elf)
Strength: Arcane Magic
Talents: Research, Decipher, Identify Arcane spell/device/creature, Heraldry
Hang-Up: Fear of spiders.
Goal: Revenge upon Dr. Korzu!

Hang-Up: a flaw, code of honour, fear, obsession, or stubborn misapprehension.
GM: design the scenario around the Goals and Hang-Ups!  This one must have spiders…

Carillion (Con Artist)
Strengths: Bluff, Convince, Negotiate
Talents: Scam, Seduce, Disguise, Read a person/situation, Distract
Hang-Up: Ultra-competitive.
Goal: Prove that I didn't kill Aurelius.

Goal: Could be achieved in this scenario. Could drive play in interesting ways. May introduce new facts or people.

Hadrian (Holy Man)
Strengths: Divine Magic
Talents: Preach, Courtly speech, Identify Divine spell/device/creature
Hang-Up: Take care of #1. Greedy.
Goal: See the elves' hidden domain.

Make up characters to suit your chosen setting/genre.

MECHANICS
Now, dear collaborator: I need you!  This game requires mechanics that let PCs do more and be more successful when they each play to their own Strengths.  Also reward actions taken to aid allies.  When the stars align, let them perform legendary feats (theme music time!).  Conversely, acting alone and outside of one's Strengths and Talents should be a long shot.

The mechanics should encourage players to occasionally bring their Hang-Ups into play.  You could also mechanize Goals.

Let conflict scenes of every kind be frantic with action, tension and comedy.  The challenge to the players is to be creative in finding ways to make their Strengths useful (or entertaining) in every situation.

Magic is tricky.  How to do a rules-light treatment of magic (no spell lists) that is flexible yet balanced?  Here's what I have in mind (modeling Gandalf):

Magic can do anything… within the game's guidelines for what can be done in a single action.
 ●	Big bonus to use magic vs. a magical foe or magical obstacle
 ●	Normal chance of success to use magic to support an ally's declared action
 ●	Slim chance of success to take independent action with no magical opposition.

GMing: DESIGNING INTERESTING SCENES
Dear collaborator, can you turn this advice into a system that enables extemporal GMing?
 -	have different scene types that spotlight each character type: e.g. combat for the Warrior, social for the Con Artist, a break-in for the Burglar.
 -	have lots of people/creatures (named NPCs, mooks, creatures, bystanders, victims…)
 -	have lots going on: a marketplace, a royal court,...
 -	have features to interact with: furniture, mounts, windows, rafters, campfire, waterfall, orchestra...
 -	have a McGuffin, victim/hostage, love interest, ambivalent "foe"...
 -	make challenges multi-faceted.  E.g.: to steal from a manse:
 -	someone distracts the occupant, while
 -	someone takes out the guards, while
 -	someone breaks in upstairs
 -	add a slowly-developing event, e.g.: a creature breaking its bonds, an alchemist charging up a death-ray machine…
 -	carry on separate scenes simultaneously

Role-play into a scene a bit, adding stuff until it feels right, before going into action resolution.

When a scene is taking shape, solicit input from the players!  Players want interesting scenes, too!  When you use a suggestion, reward the player with a bonus.

If a task involves only 1 character, expand it (things go wrong), or handwave it (they are successful).