My goal for this rule was to make defending with a shield an active, rather than a passive, ability and to create a large difference in play styles between the sword & board and two-handed combatants.
I'm really looking forward to hearing what his goals are for his game. Everybody plays the game differently because everyone gets their fun in different ways. So what follows should absolutely not be seen as a criticism of Ian or his rules. That's not my goal here at all; I'm really looking forward to seeing what he has in mind and why he's doing things the way he's doing them.
The other issue is something I've been harping on lately: when you're rolling the dice, you're not playing the game. Dice rolls are what happens when the game stops and we wait to see what sort of curveball randomness is going to throw us. People think dice rolls are the game because that's mostly what we see in the books. But games are about making choices, not rolling dice; the game of craps is in the betting; rolling of the dice only tells you who won.
So as an exercise in what-if, let's take a look at Ian's goal of making the sword-and-board warrior play differently from the two-hander. In the faux old-school game Mazes and Minotaurs, there is a rule that gives warriors in a shield wall bonuses in combat, specifically giving them a +2 defensive bonus.
If we import this rule, or one very much like it, we can see that it will encourage the sword-and-board warrior to fight with other sword-and-board warriors, shoulder-to-shoulder in a shield wall. One way to do this would be to have other fighters in the party also fight sword-and-board. That would work well for a large party, but what if the party's very small or the other players don't want to play sword-and-board fighters? It might be best for our sword-and-board warrior to instead rely on retainers, hirelings, or henchmen to fill out a shield wall. This gives us a very different sort of warrior. Now we've got a character for whom Charisma is not a dump stat. He needs that high morale bonus to keep his guys in the shield wall. He is also a lot more worried about logistics. He's got a crew to feed and transport and arm. The other warriors in the shield wall need arms, equipment, food and their own share of the loot. Our sword-and-board warrior is now more commander and leader and less of a lone-wolf like his two-hander swinging counterpart.
So now we have a sword-and-board warrior who plays very differently inside and outside of combat. The interests and concerns of the player are noticeably changed from those of a generic fighter. And we did this without adding a single dice roll, just a simple rule that modifies certain already-existing combat rolls. I suspect this doesn't do Ian much good; this is probably not the direction he wants to take his game at all. This is just a fun little exercise in thinking outside the box. Often our first instincts are spot on, but it's useful to poke around and see if they are other and better ways to accomplish our ends.
Art by Walter Crane.