The point of shields?

Shields weigh the same as armor providing the same armor class. Taking up a hand slot seems expensive for what you get, the ability to quickly throw away 1 AC/stone or to increase your AC beyond plate. What am I missing? It seems to me they are not worthwhile unless you have the fighting style (+1 AC). Also, shield AC is generally less reliable than worn armor since it doesn't protect you from behind or when you're surprised.

in addition to the fighting style, magic shields start to make the ratio of weight to AC better as well.  Other than that, the advantages are largely things that aren't necessarily modeled by the game currently.  

As a house rule I like to let players improve their saving throws against blast & breath by their shield bonus if they could reasonably interpose the shield between themselves and whatever's happening (dragon breath, fireball, etc).

The only RPG I’ve ever played that ever came close to modeling how effective a shield is in real combat is Hackmaster.

I just accept it as an idiosyncrasy of D&D and related systems that shields don’t give an appropriate benefit, because the system isn’t set up for that and just outright buffing them would be a balance issue. (For that matter, shield + fighting style shield is already a very powerful choice, nerfing its alternatives might be a way around making shields better without breaking the AC system but it would still present issues with balance relative to other choices.)

Nah man, shields are great; see my analyses at https://wanderinggamist.blogspot.com/2015/12/the-nonlinear-effectiveness-of-armor.html and https://wanderinggamist.blogspot.com/2017/07/acks-melee-offense-analysis.html . Have to run, but the crux of the thing is that every point of AC beyond 8 dramatically increases your survival time against most monsters, and it’s basically impossible to reliably break that threshold (at low/midlevels) without shields and fighting style (the main exception being plate-armored Thrassians).

In addition to the mechanical analysis going on here, shields can be used for lots of things besides just +1 to AC.  They might... block dart trap holes, keep green slime from hitting your armor, insulate you from an electified floor, keep someone from recognizing you, catch water, etc.  Don't forget about imaginative use of gear (helms are great too!)

I don't have jedavis' math, but I do note my most powergamey player rolls with plate + shield.  So in that regard it's better than it looks, although it is an oddity a shield is worth more to a heavily armored warrior than an unarmored one.

Kiero's houserule for a Greek campaign was a cloak around your arm was +1 AC, a medium shield was +2, and a hoplite's large, heavy shield was +3.

 

 

Shields are more a very good parrying device (essentially a weapon focused on defense). For an AC style system it feels like more armour (thus doesn't make them seem like a parrying device), mostly because it is more about a hit that does damage, while not including hits that do no damage (hits essentially deflect or disperse the impact)

A heavy part of the equasion comes down to how many opponents are you facing, because a dead opponent gives infinite survivablity (often an aspect that is missed in equasions, especially if your killing things much faster), after all a combatant only needs to 'survive' long enough to kill their opponent(s).

Personally for the most part they seem rather balanced when you look at things across the board, with the exception of single handed weapon (that doesn't have some basic bonus like the others).

The increased efficiency with otherwise heavy armor is one of the things that bother me, because historically you would more often see unarmored or mail equipped warriors use shields. I'm thinking they should either get the role of missile defense (+1 AC vs. missiles) or give +2 AC overall if you a wearing mail or lighter (the way I see it shields are basically damage proof in a small area, plate armor makes you damage proof overall so it's like wearing shields all over your body). This gives us some good configurations (if you care movement speed at all and want to be either 7 or 5 enc):

Plate + 2H weapon = 6 AC 7 Enc

Plate + Shield = 7 AC 7 Enc

Lamellar + Shield + Spear 6 AC 7 Enc

Chain + Shield = 6 AC 5 Enc

Scale + Shield + Spear = 5 AC 5 Enc

Ideas I had played around with for piece-meal armour (including shields) in other systems was armour essentialy had a cap (before magic or skills), though never got around to seeing it work in play.  

In respect to ACKs it would be something like a shield gives a maximum of +5 AC, but AC caps at 7 before magic and proficiencies are added.  Thus leather and shield would gain the full +5 AC from the shield, while someone in chain would gain +3 AC from the shield, and a plate user only +1 AC.  The downside of the shield is it is limited area of protection (as opposed to the armour's blanket protection), so from behind, supprised or too many opponents (more than 3) means you dont get the bonus of the shield for those attacks.

We also had Norse based C&C game where we made shields give a free parry (or instead of moving would let you do it with a weapon).  Essentially once per round a shield wielder would get a 'save' (based on their strength or dexterity with a DC equal to the opponents attack roll) to completly avoid a melee attack (ie it hit the shield and does no damage), while it still gave the typical AC bonus to missile attacks.  This got a lot of game play and worked out quite well.

Interesting ideas! I'm planning a ~1000AD campaign so I want to encourage shield and mail, but there are also samurai so it should not be strictly superior. There are no class restrictions for weapons (but thieves get a penalty to their thief skills and mages have to roll over their armor encumbrance on a D20 or have their casting time extended to next round (and possibly the one after that). This is what I'm going with.

Shields provide +1AC + 1AC against missiles

Fighters gain another +1AC if they are wearing mail or lighter. Fighting style proficiencies are not available.

This will probably result in mages and thieves using shields together with their spell or throwing weapons but I'm fine with that. Mages also get +1 to initiative when casting with a staff or wand (must be a familiar staff, used at least 1 week, wand must be crafted from a creature worth 100 x mage level XP to grant the bonus) breaking a mages staff/wand matters even when they're not actually magic items.

 

Why should any old school ruleset make shields especially good and abscond with the fun of making your own home game shield rules? I dare say that would be a far greater break with "purity" than any Proficiency / Skill rules.

Here are "my" shield hacks for ACKS:

Shields Shall Be Splintered Anytime a ready character armed and proficient with a shield takes damage that a shield might reasonably prevent they may opt to have their shield absorb the force of the blow. The character attempts a proficiency throw of 18+. If they fail, the damage is still reduced to half (round down). If they succeed, the damage is mitigated entirely. Regardless, the shield is splintered and must be discarded.1

Fight In The Shade Ready shields provide an additional +1 AC against ranged attacks if their bearer remembers.

1Characters with the weapon and shield fighting style proficiency need only a 14+ throw. In the case of spears and arrows, assume the shield's been taking a beating up until that point in other fights and the offending arrow or spear is the final straw. Any magic shields can gain this benefit freely a number of times per day equal to their plus value; a shield +2 can absorb two blows a day, but if the shield bearer uses this benefit a third time it breaks apart.

I changed the mechanical impact of shields in my game: here.

Well shields are basicly just for peope who value AC more then damage.
other that that. people who uses shields also find that raiseing their AC is easyer since buying a +1 armor and a +1 shield cost less then a +2 armor

well my GM allow the idea of a shieldwall.
if you form a line of people al having shields they all gain an additional point of AC