I'm a big consumer of popular history and i've been following a whole bunch of people online who do experimental archaeology, military history and using critiques of popular movies, etc, to teach a bit of history.
One thing thats become clear to me is that most roleplaying games, taking their clue from D&D, are terrible for authentic period weapons and armour, often getting the names wrong, along with how things are used etc.
I think Ars Magica does much better than most, but I'd like to consider expanding and rebalancing some of the weapons and armour.
In particular my next game is set in the Theban Tribunal, so I'll need to work out rules for lamellar armour, the plate reinforced chain used by the Turks and Mamluks and some new weaponry, most importantly, compound bows.
I'd also like to look at re-balancing the weapons and armours that exist in the main book. We'd need to add in Brigandine, which gets introduced in the mid 1200s, well within scope for an Ars game, which was a hugely popular form of armour. We'd also maybe want to get rid of flails (The mace and chain), change the lance to be as utterly deadly as it was from horseback (currently you are better off using an arming sword from horseback) and give the poor neglected spear a bit more ooomph.
Also rename pole axe to Poll Axe. And longsword as an arming sword. Yes, I'm a pedant.
So so I'm not making a total arse out of myself, do any of these appear in any of the supplemental books? I'm only away of the crossbow being introduced in another book.
For Armour, I'd propose expanding the vanilla list to include the following
Gambeson - Partial only - Protect 2, Weight 2
Chainmail byrnie, gambeson, gauntlets, helmet - full only - Protect 4, Weight 4
Cuir Bouille (Boiled leather armour) - Partial only - Protect 3, Weight 3
Lamellar - Partial - Protect 6, Weight 5, Full 9, load 7
Brigandine - Partial - Protect 6, Weight 5, Full 11, load 8
My reasoning here is that gambesons are actually pretty good armour, especially against slashing weapons, far better than merely quilted clothing.
Brigandine is great, but full brigandine would be worn over chainmail making it both heavier but also much safer.
I was always a little sad that boiled leather gets reduced to leather, when they are very different, boiled leather is extremely stiff and hard, not as good as metal, but miles away from merely thick leather.
Spear - - Init +2. att +3, def +1, dam+7, Str -1
Mace and chain - get rid of it
Compound bow - Init -1. att +4, def +0, dam+7, Range 20, Str +1
Certain types of spears, such as those with a large head suitable for cutting or those more like a partisan just count as polearms.