Track whether or not you have ever worn an armor piece in each slot. When you receive a non-artifact sacrifice gift, slightly bias towards slots for which you have never worn armor.

Tortles can wear hard helmets and gloves and a cloak, but as long as they wear any of these they are unable to hide in their shell.

Charm monster is generally considered too powerful and too low-level, and should probably be nerfed. Ideas:

• It only works if you’re not wearing any armor. (This is apparently how D&D does it.) Alternatively, its chance of successfully charming is reduced the more armor you’re wearing.
• Make it more reliable than it is now, but it always fails if you have other pets. (You can then only have one pet at a time without using scrolls of taming.)
• It only tames one monster at a time. (Make it a directional beam with a maximum range of 1.)
• It only pacifies monsters, and can’t be used to tame an always-hostile monster.
• Make it do what the temporary pet code in the Bard patch does: the monster remains tame for a fairly short amount of time and then reverts to whatever it was originally.
• Split into three spells: pacify monster (peaceful for charisma*2 turns), charm monster (tame for Charisma*2 turns), and dominate monster (tame permanently or for a long time).
• It only works on monsters, and doesn’t work on intelligent beings.
• It can’t directly tame a hostile monster; it can only pacify it. Peaceful monsters can then be tamed by subsequent casts, but attempting to tame a peaceful intelligent monster may anger it instead. The pacification step is dependent only on monster MR, but the taming depends on the player’s level relative to the target. The scroll of taming should remain comparatively powerful.
• Scale with skill: unskilled attempts to pacify one adjacent monster, basic to pacify all adjacent, skilled to tame one adjacent, and expert to tame all adjacent. All of these are subject to normal monster MR checks.
• Whatever nerfs do get applied, they should ensure that the scroll of taming is more powerful and reliable than the spell.

Track the highest-reached enchantment of enchantable weapons and armor. If it gets cancelled or disenchanted below this peak amount, you can dip it in a potion of restore ability to immediately raise it back to that peak.

Ring of quick change, which decreases the amount of time needed to put on and take off gear.

This could be a chargeable ring, which makes the decrease proportional to its enchantment (and a negatively charged ring making gear changes take more time). If implemented as non-chargeable, gear changes would most likely take a constant 1 or 0 turns.

One side effect of wearing this is that nymphs that charm you into taking off armor get fewer or no turns to make additional thefts while you are disrobing.

When a thrown potion of acid hits a creature, it may corrode some corrodable armor of that creature.

Canceling magical armor not only sets it to +0 but turns it into a nonmagical counterpart, which consists of new items such as “faded cloak”, “faded boots” etc. This would probably also rename “faded pall” to avoid confusion.

Armor of life saving (unspecified whether it would be magical body armor or some other sort of armor like a helm, or even an object property on existing armor). When it saves your life, it crumbles to dust like the amulet does, as well as any other source of life saving you happened to have, to prevent double-life-saving exploits.

Armor and weapons are heavier when they are cursed than their normal weight.

A horseshoe item that can be equipped on any equine creature (including player centaurs), in the boots slot. Horseshoes could deal a small amount of additional damage in kick attacks, and also deal damage based on their material, e.g. silver damage to silver-haters if the shoes are silver.

Some pieces of armor may actually be small mimics, but they don’t reveal themselves until you’ve been wearing them for a while (at which point they bite you for high damage).

Ghosts, shades, and any other incorporeal monsters can’t wear armor or wield weapons. (With a possible exception if it’s cursed.)

Armor can no longer be enchanted with a +/- number that affects AC. It always behaves as +0 with regard to AC. Instead, using a scroll of enchant armor on it gives it a random object property. A blessed scroll gives a good property, a cursed scroll a bad one, and an uncursed scroll any possible one (possibly including situational, double-edged properties that are not available as either “good” or “bad”).

If you’re wearing some orcish armor, some orcs may see you as another orc and be peaceful. Possibly the chance of this happening is higher for each piece of orcish armor you are wearing.

If you tell a vault guard that your name is Croesus, and you are wearing gold armor, they might lead you out of the vault without forcing you to drop any gold. The chance of this outcome increases for each piece of gold armor you are wearing.

Revamped combat system:

1. All melee attacks randomly select a specific area of the body to hit, as well as regular misses, all out of the same pool.
2. Higher skill biases the pool “inward” on the body - some of the miss percentage will turn into outer limb hit percentage, some of the inner limb hit percentage will turn into a body hit percentage, etc. Head strikes are rare, but can inflict stunning as well as damage, although helms mitigate this somewhat.
3. Armor protects the area it covers, but its material or AC is a big factor in damage reduction: weak cloth armor takes full damage just like no armor, plate armor generally reduces damage completely except for rare armor-chink hits, etc.
4. Armor is strictly organized into four tiers of cloth, leather, mail and plate.
5. Positive weapon enchantment lowers the armor’s effective tier. Positive armor enchantment raises its effective tier. High armor enchantments are made substantially harder to come by.
6. Thrown daggers and knives are effectively useless against mail and plate armor, except for rare chink hits. Bow and arrow is useless against plate armor unless enchanted. Crossbow, however, is still useful against it. However, a successful shot deals a lot of damage.
7. On the monster side, many monsters (e.g. dragons) have effective full-body enchanted plate. Some monsters such as giants may also have powerful attacks that bypass armor.
8. Along with the limb-targeting system, it is also possible to break limbs. Broken limbs can be cured with prayer or most types of healing.

Different roles have different speeds for putting on armor, because they have varying amounts of practice with it. In particular, combat-heavy roles such as Barbarians, Valkyries and Samurai should continue to use the existing armor delays, whereas roles like Archeologists and Tourists should take longer to wear armor pieces.

You can’t safely wear more than N total points of enchantment on all your armor at once. More than that, and armor pieces may start randomly exploding.

If you aren’t wearing armor or a shield and have high martial arts/bare hands skill, you get an AC bonus (probably a higher one for martial arts). The bonus should probably scale up with higher skill, and should be generally higher for martial arts users than bare hands users.

Weapons and armor that generate in shops can be randomly eroded at any erosion level. Perhaps 10% or 20% of items are eroded, the rest are not.

Monks can gain intrinsic immunity to just about everything by leveling up, but most of these are nullified if the monk is wearing body armor.

Make orcish armor out of bone rather than iron.

Jetpacks, a chargeable source of levitation/flying. They are worn in the cloak (or body armor?) slot and grant 0 AC.

Rebalance armor so that all “mail” armor and most of the iron body armor in general is not useless. Ideally, the worst iron armor (orcish chain mail) should be considerably better than studded leather, but they are equivalent. The ideal balance, keeping leather armors and all weights constant and not accounting for to-hit or damage reduction, is probably something like the mails going up to 9 or 10 AC, and splint and plate getting up to around 14, but this is not possible to implement without changing the combat system.

Armor should make use of its corpsenm (monster index) for efficiency and to do interesting things that are not currently done. For example, this would allow dragon scales and scale mail to be merged into two items that use the various dragon monster indexes to figure out its special effects, and it would allow for fireproof low boots created from polypiling a crocodile corpse to be flavored differently. In variants where applying dragon properties to other pieces of armor is being considered or planned, this would provide an easy way to do so.

Also see dtsund’s dragon scale mail proposal.