Jack of Plates

[B-Type]

So realizing brigandine armor is basically just a mail hauberk with an armored doublet over the top of it, I'd wondered if anyone had ruled the doublet it could be worn over a different kind of armor, such as perhaps padded armor, which was done frequently with the actual type of armor it's based off of at times, perhaps taking the difference between mail and brigandine in terms of armor, AP, and Bulk and "adding" it on top of other armors?
Knights even wore brigandines over their plate at times way back when.

[stew31r]

You don't need the hauberk for a brigandine. A brigandine is two layers of leather or heavy fabric with leather or metal plates sandwiched between them. It was worn as stand alone armor with nothing under it, over a hauberk, or over a gambeson.

[B-Type]

Yes, but the stats for the armor itself always include the hauberk, since it mentions you can remove the brigandine and just wear mail armor in the book.

[Kival]

Though the Jack of plates and the brigandine are not exactly the same, we can consider them the same for the sake of game mechanisms. I indeed made rules for wearing brigandine on it's own without the mail hauberk as I did for some others too. The general idea for it came from another user in the forum. Anyway, my armour values are not exactly the same as in the "vanilla" game, so it's probably not copyable one to one. I did make seperate values for Brigandine with or without Mail Hauberk:

Brigandine 4 -2 1
Brigandine (Mail) 8 -4 3

(Mail is 6 -2 3 in my game though)

The reasoning behind it is, that I don't see a big difference between ringmail and brigandine, both beeing fairly light heavy armour ("medium armour"). The advantage of the brigandine is that it can easier be used together with a mail hauberk and it's easier to hide that you're wearing armour at all. For a discussion regarding the authenticity of ringmail I'd recommend some older threads.

[B-Type]

Not so worried about authenticity. Westeros heavily favors the usage of the sword, when the sword is pretty much the most useless weapon in the world against heavy plate armours, so clearly historical authenticity is kinda loose in Westeros. Thanks for the input though!

[Kival]

Westeros heavily favors the usage of the sword, when the sword is pretty much the most useless weapon in the world against heavy plate armours, so clearly historical authenticity is kinda loose in Westeros.

I'm inclined to disagree. You're right though, that Westeros is not very authentic in this regards but swords have been favored historically too despite their relative weakness against heavy armoured enemies.

a) Swords and lance were historically considered the knightly weapons while Axes and maces etc. were considered unknightly.

b) In europe swordstyles had been developed to fight plate-armoured enemies and swords developed into some kind of thrusting instead of slashing weapon.

[B-Type]

I'm inclined to disagree. You're right though, that Westeros is not very authentic in this regards but swords have been favored historically too despite their relative weakness against heavy armoured enemies.

a) Swords and lance were historically considered the knightly weapons while Axes and maces etc. were considered unknightly.

b) In europe swordstyles had been developed to fight plate-armoured enemies and swords developed into some kind of thrusting instead of slashing weapon.

Maces and warhammers actually got used more often as plate became more advanced, and quite often were considered "knightly" weapons. Unique sword tricks were used to piece armor, but these swords were large. The kind of sword Jon Snow ends up using is the kind of sword nearly everyone used when plate was invented, called a bastard sword in Britain and just a longsword everywhere else (because it was really long, not medium-sized like many swords), and the techniques for beating armor involved "half-swording" and almost using the weapon like a spear, not a sword, and most notably involved a two-handed grip, while many Westerosi seem to heavily favor usage of shields, probably because the "longsword" described in the book is more of an arming sword, which got used quite a bit with shields.
Though I note that in most of the battle scenes, many characters DO seem to be using much heavier weapons then a simple sword: Loras Tyrell is mentioned to he using a morningstar, Robert has his big-ass hammer, and greatswords are all over the place. Many of the characters using regular swords end up drawing them when not expecting trouble.