Something I've realized in my time surfing through the various boards and talking to other gamers. Gamers, despite a real interest in fantasy, typically don't have a clue when it comes to things medieval. Web boards are replete with people honestly expounding the virtues of a 25 pound sword, or armor so heavy you cannot walk, or longbows with a 150 pound draw weight. I see this fairly often where ever I go. I think a one or two page feature in Dragon might go a long way to helping the situation.
Every article could focus on a different, historically (fairly) accurate element that comes up in the game. Obviously weapons and armor would be a good start, but even other things like manufactured goods, basic items like lanterns and backpacks, even trail rations and sanitation issues could be focused on.
I don't know about anyone else, but I think a page or two every month would be well spent on this sort of thing.
Amen to that, brother. (Card carrying member of the SCA, myself.) So many little details of history would make D&D in general more practical. Knowing a good foundation in history would make your campaign more believable.
Here's some History ideas I've had myself:
Pirates (with Stormwrack out, this could be fun!)
Siege Engines
Bows & Crossbows
Merchant Empires
Nomadic Tribes
...for a start!