The goal is to allow more gridless play (either excluding or in addition to grid-based combats). This could allow different styles of play (like the gridless combat I experienced in my AD&D days), while still keeping position-based powers somewhat relevant.
What play looks like: you verbally trade descriptions and take actions. The DM adjucates the exact positioning of people in combat, but generally goes with what the players propose. When players slightly stretch their movement and position, the DM keeps track of this “Movement Advantage” and later compensates the opponents accordingly. This keeps explicit negotiation of “who can go where” to a minimum.
(This does place some more work on the DM to adjucate on the fly, and requires more trust between the DM and players to simply roll with the adjucations rather than negotiating them during the action. IME, most groups can handle something this just fine.)
(1) The DM should have a handle on the space of the encounter, either by sketching a rough map or keeping it in your head. (If you prefer, feel free to convert all mention of squares to increments of 5 feet.)
(2) When range is in question – for movement actions, forced movement or ranged attacks – the player should describe what the movement/range and what they’re to accomplish. The DM can clarify/block the action if it’s unfeasible, but should generally accept the player’s suggestion.
If the movement is acceptable but *might* require another square or two of movement, the DM should give himself a point of Movement Advantage in his notes. The DM doesn’t need to announce this, but instead should keep the action moving.
If a power or condition is part of a movement/range, the player should mention this. (If a power is used for positioning, the DM should tend towards accepting the player’s suggestion.)
(3) When the DM is controlling creatures, the DM can spend points of Movement Advantage to stretch movement and range by another square or two when the exact range is questionable. The DM should aim to spend these soon after they’re created (so that the number of Movement Advantage points generally stays around zero), and try to spend around the player who created the Advantage.
When in doubt: let the dramatically obvious and reasonable thing for the fight happen, and let the players (and monsters) see their intent happen. Movement sets up the use of the power and attacks that you want to see.
Bonus option: If Movement Advantage is piling up, the DM could spend this in new ways: 3 points for shifting an extra square, or 5 points for taking an extra move action. (Of course, such spending isn’t exactly balanced, but it can keep things moving and open up new possibilites.)
Copious examples follow! Dialogue in quotes, with thought bubbles in curly parens.
(a) The standard move: “I move in from the doorway to engage the assassin, pinning him against the bar, and then punch him in the face.”
DM: (The bar is about 30 or 40 feet across?) “What’s your speed again? 6? Ok.” (Yeah, that sounds fine.)
or, DM: (The bar is definitely more like 7 squares away. I’ll accept it and take a Movement Advantage for later.)
(b) The shift: “I shift away from the barbarian, towards the door, use my second wind and draw my weapon.”
DM: (There’s no one on that side of the bar near him; sounds fine.)
(c) A justified maneuver: “I use my Monk Power to shift two and get out of range from the two bodyguards.”
DM: (It seemed like the two body guards were close and even with a shift she’d be near one; but two shifts might do it, and it is a power. I’ll go with it.)
(d) A sketchy shift: “I shift away from the Barbarian and next the Rogue so that I can attack him.”
DM: (That doesn’t seem right; there’s a good twenty feet or so between the two, and a shift wouldn’t cut it.) “If you shift, you’re not quite far enough to reach the rogue. He’s more like 20 feet away. Do you want to simply move rather than shift?”
or, DM: (Does it take 1 or 2 squares to reach the rogue? I think it’s somehwere in the middle, so I’ll take a Movement Advantage for later.)
(e) A cautious move: “I move around to the other side of the two foes so that I can flank the bad guy. I walk around them so I don’t provoke an attack. My speed is 6.”
DM: (Getting there is just 5 squares, except the direct route would provoke an attack; going around them would be 6 or 7 squares. I’ll go with it and take a Movement Advantage for later.)
(f) An awesome push: “I use Awesome Shove to push the boss 1 back into the cauldron, causing whatever fire damage that causes.”
DM: (Okay, that’s awesome, but it’s more like 3 squares. I’ll go with it and take a Movement Advantage point.)
or, DM: “You can push him back but the cauldron is too far away, so he remains unscathed.”
(g) A ranged attack: “I peek through the window and shoot an arrow at the guard accross the street. The range is 10.”
DM: (It’s more like 60 feet accross the street. I’ll allow it and take a Movement Advantage.)
(h) Spending your Movement Advantage:
DM: (Their cleric is in the back, just beyond the Wyrmpriest’s range 10 attack. But I’ll spend two points of Advantage here and make it happen.) “Stinging Blindess strikes the cleric! That teaches you to hide from me!”