- Treat it as a combat trick, rolling a d6 for a Change Situation roll. For this kind of trick, I might consider dropping the d20 attack roll beforehand.
- Treat it as an issue of speed, rolling a d6 and comparing the result to the length of the opponent's weapon in feet; if the d6 is lower than the weapon's length, the "attacker" can move out of the opponent's strike zone before the opponent can strike. This maneuver replaces the attacker's normal attack.
But the diagram is not about that.
I'm really more concerned about dispelling myths about not being able to reach an opponent. In the LBBs in a couple places, the rules mention that opponents within 1 scale inch of each other are considered to be in melee. I'm worried that some people, either complete newbies or those more used to precise miniatures-based combat systems, might think that this is a nonsensical rule. The reality is that, given the size of a human figure, the typical reach of a fully-extended arm, and the extra reach provided by even short weapons, an attacker can actually strike an opponent in many areas of that 10x10 square. Even those areas outside the attacker's reach become reachable with a lunge or a step. For the purposes of a 1-minute combat round, we can assume that an attack will be able to reach its target unless the opponent actively and successfully evades.
The other concern I have is the length of weapons and gear when carried in a dungeon. Even assuming a 10' ceiling, you won't be carrying some polearms in a dungeon except horizontally, and you might have to carry a 10-foot pole horizontally as well in most areas; you certainly won't be able to stand one up vertically or carry it crossways across your body when trying to walk through a door. The diagram is meant to be a reminder to think about your equipment and how it will actually "fit" into a dungeon environment.
Another thing the diagram is meant to show is how much space people can actually take up just standing there. Imagine that image in the previous post is a 10'x10' room. Imagine there are more figures in the room; you could fit 9 figures in the square in an orderly formation. But that's assuming there's no chest or other object in the room. And even if there isn't, and you fit a party of 9 into the room, what if the doors open inwards? The room is going to become a little more cramped in such cases. And melee with more than four figures is going to be more of a pileup than a duel. Which, I suppose, is why they call it "melee".
I'm thinking of a diagram or possibly a series of diagrams as a sort of visual instruction on what dungeon exploration would look like. Maybe this will have to wait for a later version of the rules, though.