5E D&D's armor inconsistencies

I earlier concluded that medium armor is valued more highly than light armor in 5th edition D&D. Well, that's actually not completely true.

Armor proficiencies are balanced really strangely in 5th edition D&D, but that is due to a number of complications such as:
a) Rogues and rangers need light armor to be equal in value to medium armor
b) Light armor users often increase their Dexterity score, but not always

But before we get into that, let's first look at the expected armor values of a level 1 character. At level 1, we expect the dexterity based classes to have at least 16 dexterity so they have a modifier of +3. Medium armor users will often have +2 dexterity modifier in order to max out their armor class while wearing medium armor. Heavy armor users don't care about dexterity. The elf is the most popular race for the wizard who wears no armor, and will almost inevitably have a +3 dex modifier at level 1.

So at level 1, we expect:
None: 10+3= 13 AC
Light armor (Leather): 11+3=14 AC
Medium armor (chain shirt): 14+2= 15 AC
Medium armor (Scale mail): 14+2=16 AC, disadvantage in stealth
Heavy armor (Chain mail): 16 AC, disadvantage in stealth

The medium armor and heavy armor users have the same armor class at level 1. I know this, but always thought it was more than a little odd. Looking at these numbers, it seems like the only real benefit heavy armor provides over medium armor is that the heavy armor users don't need to invest in dexterity at all. And it seems almost obvious that medium armor is better than light armor and should be valued more. Right? Not really.

What happens at level 2 or earlier throws this assumption off. Studded leather armor is really cheap, a minor 45gp. It's cheaper than some of the starting medium and heavy armors. In comparison, the next upgrades for medium armor, breastplate and half plate, each cost 400gp and 750gp (They'll afford it maybe level 4/5). The upgrade for heavy armor, splint mail, costs 200gp (they'll afford it around level 3). In comparison light armor users may afford studded leather even before they reach level 2 especially if the party pools their money.

So at level 2 or earlier, we expect:
None: 10+3= 13 AC
Light armor (Studded Leather): 12+3=15 AC
Medium armor (chain shirt): 14+2= 15 AC
Medium armor (Scale mail): 14+2=16 AC, disadvantage in stealth
Heavy armor (Chain mail): 16 AC, disadvantage in stealth

So very soon, light armor looks just as good as medium armor. Hrm.

Furthermore, that's not how it ends. By level 8, the PCs users can almost certainly afford the best (non-magical) armor money can buy. Dexterity-based characters will have pumped up their dexterity to the hard cap, gaining a +5 dex modifier. The wizard and sorceror will probably push up their spellcasting ability score instead so their dex mod remains at +3. By then however they are probably casting Mage Armor on themselves regularly since they have plenty of low level spells to spare.

So at level 8, we expect;
None: 13 OR 13+3= 16 (Mage armor)
Light (Studded leather): 12+5=17
Medium (Breastplate):  14+2=16
Medium (Half plate): 15+2=17, disadvantage in stealth
Heavy (Plate): 18, disadvantage in stealth

And now heavy armor and light armor have leaped ahead, leaving medium armor in the dust. What gives? In the long run, light armor is MORE valuable than medium armor as it flat out beats the armor class of the breastplate-wearing druid who also wants to sneak around. The developers are sending us pretty mixed signals here. Is medium armor better than light armor or equal in value?

Another odd duck is the Mage Armor caster at level 12/16 who decided to sink points into dexterity now that their spellcasting ability score is maxed. They'll end up with 8AC, the same as the heavy plate users. Now the mages are tanks! I don't think the system should encourage wizards to think they are frontliners (they still are not).

a) Rogues and rangers need light armor to be equal in value to medium armor

This end result we see at level 8 is probably caused by the poor rogue and ranger. These two classes use light armor usually, but by tradition they are meant to be in melee and therefore need better protection. So by level 8 they get as much AC as medium armor users while wearing light armor. So at least for the ranger and rogue, light armor has the same value as medium armor. The trouble is, the game is being awfully inconsistent. What about the rogue and ranger wading into melee at level 1? Rangers could choose to  use scale mail instead, but the poor rogue has an AC of 14 at level 1. Even stranger, why does the heavy armor user have the same AC as the medium armor user at level 1 but not at level 8?

Perhaps another part of the problem was with our initial assumptions. We had assumed non-dexterity based classes like druids and clerics are going to max out their AC while wearing medium armor at level 1 by pushing their AC to a +2 modifier. Let's instead make the unlikely assumption that medium armor users only marginally invest in dexterity for a +1 modifier. So at about level 1 we'd instead expect:

None: 10+3= 13 AC
Light armor (Leather): 11+3=14 AC
Light armor (Studded Leather): 12+3=15 AC
Medium armor (chain shirt): 14+1= 14 AC
Medium armor (Scale mail): 14+1=15 AC, disadvantage in stealth
Heavy armor (Chain mail): 16 AC, disadvantage in stealth

And suddenly these numbers look consistent with what happens at level 8.

b) Light armor users often increase their Dexterity score, but not always

What about the classes which have often have some dexterity but don't invest more until much later? Even though Warlocks and lore bards use light armor, they are likely to stay at 16 or even 14 dexterity for some time since they need to push up their charisma instead. HOWEVER, both these classes can have access to Mage Armor. It looks like they were expected to cast Mage Armor on themselves anyway.

Just WHO uses medium armor anyway? Druids, barbarians, valor bards and a few uncommon cleric domains. Sometimes the odd strength-based ranger. These characters would not be pushing up dexterity until much later either.

Anyway, if we look at characters who do not push up their dexterity at level 4 and 8, we'd instead see at level 8:

None: 13 OR 13+3= 16 (Mage armor)
Light (Studded leather): 12+3=15
Medium (Breastplate):  14+2=16
Medium (Half plate): 15+2=17, disadvantage in stealth
Heavy (Plate): 18, disadvantage in stealth

In this case medium armor looks more desirable compared to light armor, doesn't it?

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I'd rather the differences between light, medium and heavy armor be a little more consistent from level 1 to level 20. So let's tweak the armor values.

And so!

Armor
Armor	Armor Class (AC)	Strength	Stealth	Start AC	EndAC
Light Armor
Leather	11 + Dex modifier	—	—	14
Studded leather	12 + Dex modifier	—	—		17
Medium Armor
Hide	12 + Dex modifier (max 2)	Str 9	—	14
Lamellar (leather)	13 + Dex modifier (max 2)	Str 9	—
Chain Shirt	14 + Dex modifier (max 2)	Str 9	—
Breastplate	15 + Dex modifier (max 2)	Str 9	—		17
Medium Armor (bulky)
Ring mail	14 + Dex modifier (max 1)	Str 11	Disadvntge	15
Lamellar (steel)	15 + Dex modifier (max 1)	Str 13	Disadvntge
Scale Mail	16 + Dex modifier (max 1)	Str 13	Disadvntge
Half Plate	17 + Dex modifier (max 1)	Str 13	Disadvntge		18
Heavy Armor
Chain Mail	16	Str 13	Disadvntge	16
Splint	17	Str 15	Disadvntge
Brigadine	18	Str 15	Disadvntge
Plate mail	19	Str 15	Disadvntge		19

Okay, looks good. I would probably extend those by 2 steps in order to keep up with high level Mage Armor casters. So we can extend those with exotic materials the players encounter in the higher levels such as mithral, ironwood, adamantine and dragon leather/scale.

So at least in our system, light armor has consistently the same value as medium armor.

And since our system is designed to have flexible flavor, all the armors listed above can be "re-flavored".
-"Can I start with bone armor instead of Hide? "
Sure, no problem. Same stats as hide, just more, well, bone-y.

-"Ah, I got an exotic chitin of an ankheg I want to make some good quality armor with."
Sure, it'll make a lightweight plate armor (Player is currently wearing splint mail. So best make it equivalent of brigadine)

-"They're wearing ceramic breastplates? Cool, I'll want to loot one of those later."
(It's the equivalent of scale mail maybe)

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Let's go back to our Feature Point system. Conveniently, if we assign light and medium armor proficiencies a value of 1 FP and heavy armor proficiency a value of 2 FP, the fighter's features (not including second wind) at level 1 total up to a neat 8 FP. 2 (D10 hit dice) + 2 (Martial weapon prof) + 2 (Heavy armor prof) + 2 (Fighting style) =8. If we assign second wind a value of 2, the fighter's total FP value at level 1 is 10 FP.

I decided to assign Wizard spell-casting an even value of 8FP at level 1. Arcane recovery seems synonymous to second wind, so it costs 2FP. And hey! The wizard meets also uses 10 FP at level 1.

So PCs start with 10 FP at level 1, gaining 6FP every level-up. 10 is a nicer number than 12 anyway. :p

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You may have noticed I also tweaked the strength requirements a bit. Simple reason: Armor proficiencies are way too easy to get in a classless system.  Even in 3rd and 5th edition, Heavy Armor proficiency is something that you can relatively easily by sinking a single level into the fighter class. In a classless system this issue is compounded manifold since players can spend a cheap cost of 2FP at any time to get access to the best armor. I'm not keen on reintroducing arcane spell failure. The better solution I think is to increase the Strength requirement for the bulky armors. The armors which are not bulky require some dex and are comparable to Mage Armor anyway (13+dex mod).

I will however bring back opportunity attacks vs ranged spells. After all, I want to encourage the mobile Rogue-type characters to sneak up on enemy mages in melee. So ranged spells once again provoke attacks of opportunity. Spells with a range of "self" like Burning Hands, Thunderwave, Expeditious Retreat and Shield are not affected.

In my current campaign, one of my players kept pushing his sorcerer into melee in order to cast magic missiles. A dubious tactic for sure. A good system should provide feedback immediately so the player realises he's playing badly sooner: opportunity attack. I'm leaning towards allowing the opportunity attack to force a concentration check if it hits and cause the spell to fizzle.

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Update: For comparison with 5E, here's a table of how light vs medium vs heavy armor in 3rd edition/Pathfinder

Light Armors
Armor	Cost	Armor/Shield Bonus	Maximum Dex Bonus	Dex 18(+4)	Dex 20(+4)	Dex 22 (+5)
Padded	5 gp	1	8	5	6	7
Leather	10 gp	2	6	6	7	8
Studded leather	25 gp	3	5	7	8	8
Chain shirt	100 gp	4	4	8	8	8
Medium Armors
Hide	15 gp	4	4	8	8	8
Scale mail	50 gp	5	3	8	8	8
Chainmail	150 gp	6	2	8	8	8
Breastplate	200 gp	6	3	9	9	9
Heavy Armors
Splint mail	200 gp	7	0	7	7	7
Banded mail	250 gp	7	1	8	8	8
Half-plate	600 gp	8	0	8	8	8
Full plate	1,500 gp	9	1	10	10	10

Keep in mind that at level 1 you start with about 150 gold and a lot of it needs to be spent on provisions and useful things other than armor and weapons. I'd say players should spend at most 100 gold, but 75 or lower is safer. Looking at these tables, it's pretty obvious that in Pathfinder medium is better than light, and heavy is better than medium (although you can't afford heavy at the start).