Armor Options

There are several things I don't like about the armor options in 5e. There is very little choice, and it constrains you to a narrow set of archetypes. Characters who only have light armor proficiency will always wear studded leather as soon as they get any spare cash; the other options might as well not exist. And the heavy armor proficiency is worthless for dex-based fighters, or anyone who doesn't want to make the party fail all of its stealth checks. The only meaningful choice is in medium armor, where you can decide if you want more protection or more stealth.

I also don't like how the armor table balances things by cost. Anything that costs 100 gp or more should be part of the treasure tables, and treated the same way as magic items. It makes no sense from a socioeconomic perspective that high-end plate armor is assumed to be generally available for purchase but a Broom of Flying is not. The armor costs 1500 gp and is only useful for a few characters, but the broom costs 500 gp to create and is useful for anybody. There is a much larger market for the brooms, and they are much more militarily useful, which means more of them would be produced. Yes, it is difficult and expensive to produce magic items, possibly requiring a small civilization's worth of expertise and supply chains. And they may be considered a military asset that civilians are not allowed to own. But the same thing is true of advanced plate armor.

From a worldbuilding perspective, the game has historically assumed a Dark Ages environment where plate armor was rare and expensive, and the armor table reflects that. But in recent years, the game has shifted more to an Early Modern or Renaissance kind of baseline, especially in settings like Ravnica, Eberron, or the more developed parts of Forgotten Realms. By the 1400s, there was a cheap mass-produced form of plate armor called munition armor. I think it makes sense for this to be available to starting characters, especially because from a character design and flavor perspective, a lot of people want to imagine their character in plate armor from the beginning.

New Armor Table

This table repalces the armor table on page 145 of the PHB. The categories of Light, Medium, and Heavy armor are replaced with Simple, Martial, and Elite armor. Characters who would be proficient in Light armor are instead proficient in Simple armor, etc.

Armor	Cost	Armor Class (AC)	Strength	Stealth	Weight
Simple Armor
Leather	10 gp	11 + Dex Modifier	-	-	10 lb.
Hide	10 gp	12 + Dex Modifier (max 2)	Str 8	-	12 lb.
Reinforced hide	20 gp	13 + Dex Modifier (max 2)	Str 9	Disadvantage	20 lb.
Thick hide	20 gp	13	Str 10	-	30 lb.
Ring mail	30 gp	14	Str 11	Disadvantage	40 lb.
Martial Armor
Studded leather	30 gp	12 + Dex Modifier	Str 8	-	13 lb.
Chain shirt	30 gp	13 + Dex Modifier (max 2)	Str 9	-	20 lb.
Scale mail	40 gp	14 + Dex Modifier (max 2)	Str 10	Disadvantage	30 lb.
Thick mail	40 gp	14	Str 11	-	40 lb.
Plated mail	50 gp	15	Str 12	Disadvantage	45 lb.
Elite Armor
Light chain	50 gp	13 + Dex Modifier	Str 9	-	20 lb.
Breastplate	50 gp	14 + Dex Modifier (max 2)	Str 10	-	30 lb.
Half plate	60 gp	15 + Dex Modifier (max 2)	Str 11	Disadvantage	40 lb.
Muffled plate	60 gp	15	Str 12	-	45 lb.
Heavy plate	70 gp	16	Str 13	Disadvantage	55 lb.
Shields
Buckler	20 gp	+1	-	-	2 lb.
Shield	10 gp	+2	+2	-	6 lb.

I kept the existing armor wherever possible, changing only what was needed. Breastplate and half plate are now cheap enough for starting characters, but require an extra level of proficiency and also a minimum strength score. Studded leather now requires the second level of proficiency, while hide and ring mail are available to those with only the lowest proficiency. The thing that the book calls chain mail is heavy plate on my table. To prevent confusion, all new armor types have new names, and I don't use the names 'chain mail' or 'plate'.

Shields now increase the strength requirement of the armor by 2. (This prevents high-dex fighters from getting extremely high ACs unless they also have decent strength.)

If you are using the class's listed starting equipment, allow characters to replace their armor with anything from the same type. For example, anyone who starts with leather armor could start with any simple armor. Most character classes will have more options now. The only class that is definitely worse off is the Rogue. They lost studded leather and don't care about the low-dex options. My games are very skill-intensive, which helps rogues, so I'm okay with this, but in a dungeon crawl campaign you may want to make +1 leather armor relatively cheap and easy to purchase.

Treasure

+1 armor of any type is now an uncommon item, and +2 armor is a rare item. However, given the increasing returns to AC, +3 armor is still a legendary item. If the armor has a strength requirement, it increases as much as the AC. The strength-requirement increase of shields also increases by +1 for each +1 AC the shield has. (For example, a fighter with +2 light chain and a +2 shield will need a Strength score of 15 to avoid having their speed reduced by 10 feet. With a +2 buckler, they would need a Strength score of 13.)

The thing that the book calls splint is +1 heavy plate in this system, and the thing it calls plate is +2 heavy plate. (I'm pretty sure that the book's system was distorted by the existence of its AC 18 plate armor, and the expensive medium armors that are basically a +1 version of starting gear. They needed a way to prevent players who randomly got a magic version of those from being overpowered. But the implementation was clumsy, and feels like a last-minute edit. It is just dumb that a +1 version of low-end armor costs thousands while the mundane upgrade costs hundreds, and I think that the armor table has the appropriate upgrade cost.)

Any magic armor in the book that says 'medium or heavy, but not hide' is now 'martial or elite, but not studded leather'. Mithral armor of any type that does not normally cause a stealth penalty can be worn under normal clothes. Demon armor can be of any type, gives +2 AC, and will look like ordinary +2 armor upon inspection. Dwarven Plate can be any martial or elite armor. Plate armor of ethrealness can now be of any type and gives +2 AC.

If using the book's treasure tables, make the following adjustments:

Table F: A roll of 01-05 is +1 armor of a random type. A roll of 66-68 is adamantine armor of any appropriate type. (If you are concerned that this gives out fewer magic weapons, then you can introduce NPCs who will give them a random +1 weapon in exchange for items they don't want.)

Table G: All of the +1 armor results are replaced with +2 armor of a random type. All of the resistance armor results are replaced with resistance armor of a random type. All of the adamantine armor results are replaced with +1 adamantine armor of any appropriate type.

Table H: All of the +1 armor results are replaced with +2 mariner's armor of a random type. All of the +2 armor results are replaced with +2 mithril armor of any appropriate type.  All of the resistance armor results are replaced with +1 resistance armor of a random type. All of the adamantine armor results are replaced with +2 adamantine armor of any appropriate type.

Table I: All of the +1, +2, and +3 armor results are replaced with +3 armor of a random type. All of the resistance armor results are replaced with +2 resistance armor of any random type.

Random Armor

Treasure tables often call for a random armor type. Roll a d20 on this table.

To roll a random nonmetallic armor, roll d10.

To roll a random metallic armor (e.g. for Mithril and Adamantium), roll d10+10.

1-2: Leather

3-4: Hide

5-6: Reinforced hide

7-8: Thick hide

9-10: Studded leather

11: Ring mail

12: Chain shirt

13: Scale mail

14: Thick mail

15: Plated mail

16: Light chain

17: Breastplate

18: Half plate

19: Muffled plate

20: Heavy plate

Option: Improvised Armor

The following armor types can be created for free during a short rest by any player who has an appropriate tool proficiency, and access to basic materials scavenged from the environment. Usually it involves attaching various things to one's clothing to try to cover vulnerable areas. They each require Simple armor proficiency to wear:

Armor	Cost	Armor Class (AC)	Strength	Stealth	Weight
Simple Armor
Padded	-	11 + Dex Modifier	-	Disadvantage	8 lb.
Hide scraps	-	11 + Dex Modifier (max 2)	-	-	12 lb.
Reinforced padded	-	12 + Dex Modifier (max 2)	Str 9	Disadvantage	20 lb.
Thick hide scraps	-	12	Str 10	-	30 lb.
Plated padded	-	13	Str 11	Disadvantage	40 lb.