History and fiction often has characters complain that they are unarmed and therefore unable to defend themselves. It’s often held as a point of honor to allow an opponent to arm themselves rather than be defenseless. Yet, D&D has always assumed that an unarmored character has a (traditional, descending) AC of 10, making attacks against them a coin toss for goblins and orcs; that’s too hard.

My experience (from the ’80s and ’90s) is also that players got too good of an armor class too early and that DMs didn’t really need to give them magic armor. The problem was that, as soon as they got their first treasure, they bought platemail and shield, giving them a (traditional, descending) AC of 2, which took a goblin an 18 to hit; that’s nigh invulnerable.

If you do nothing else, consider this armor class fix.

Armor Class

A character with no armor, shield, or weapon has an armor class of 5 (with ascending AC) or 15 (with old-school descending AC). High dexterity improves that. Wearing armor can greatly improve that, and having a melee weapon and/or shield gives you a bonus. Note that a magic weapon does not lend its bonus to armor class.

You can, of course, only get a benefit from one suit of armor, one shield, and one weapon at a time.

Defenses

Armor Class	Defense	Encumbrance
+3	Dagger, medium flail, or 2-handed melee weapon	per weapon
+4	Medium (1-handed or hand-and-a-half) melee weapon	per weapon
+2	Buckler/small, light shield/improvised object	1
+3	Medium shield	3
+4	Large shield	4

Armor

Armor Class	Armor	Encumbrance
+2	Padded gambeson or hardened leather	0
+3	Studded leather, ring, or hide	0
+4	Coat of mail, scale, brigandine	0
+5	Splint, banded, or plate and mail (shields are -1 less effective)	1
+6	Plate armor (shields are ineffective, DEX is -1)	0

Now, a character without armor but carrying a staff would have armor class 8 (12 with descending AC). A character in plate & mail and carrying a shield and longsword would have an armor class of 16 (4 with descending AC). That makes combat a bit more dangerous and allows the DM to give better magic armor.

A character in plate armor has an AC of 15 (5 with descending AC), because shields are not helpful (your body is basically covered in shields) but also has no encumbrance penalty.

It’s historically accurate that fully armored knights didn’t use shields. And it’s also accurate that losing your weapon made you much more vulnerable.

Now wizards carrying a staff have an AC of 9, because they can defend themselves somewhat. In my game, a staff is one of the sorcerous channel items that can act like a 5e arcane focus. (Others include wand, amulet, crystal, and orb.)

Optional Improvements

Roll 4d6; drop the lowest die–unless you got more than one 1, then keep all four. This is your charisma. Roll 5 more times the same way and assign these to abilities as you like. If no score is at least 15, raise your second highest score to 15.

As characters progress, they gain 2 hp for magic-users, 3 for clerics, halflings, and elves, and 4 for fighters and dwarves. However, you should give PCs and NPCs an extra 6 hp each.

If they are reduced below 8 hp, they are injured and get -3 to attacks and strength and dexterity checks. This way, characters are a little tougher, but if they are reduced to just a few hit points, they aren’t continuing to fight normally.

If they are reduced to zero hp, they are seriously injured and must save (paralyzation, poison, or death magic) or die. These makes combat a bit less lethal despite the heroes being more likely to get hit. I wrote complete rules for injury and dying previously.