Low-magic alternatives
Hello Narfellus,
The D&D game is designed that as characters increase in level, they get those spells, magic items, etc. to increase their AC; however, if you want to run a low-magic campaign, then the obvious result is that the campaign is going to be a lot deadlier, and some monsters will nigh industructible, because by virtue of being able to hit the party's characters a lot more often and the party at a serious disadvantage of not being able to deliver more punishment in return. Even creating feats where a player gives up something for AC will get old, because then it reduces the effectiveness in a combat situation (you have a bunch of character just defending themselves, and hoping that a 20--their only 5% chance to hit a monter--will be rolled enough times to win the encounter because they gave up their BAB, other abilities that would normally make them effective combatants useless). Do this in every encounter, and it will get old real quick, particularly if your players are of the type who like to fight monsters they run into.
If you still want to run a low-magic campaign, but keep the same levels of action in your game in a typical D&D session, then a possible option is to create feats and skills, but don't have them penalize character capabilities. For example--if you want to remove armor and weapon enhancement bonuses, you can create a feat like armor specialization and weapon specialization that provides a +1 enhancement bonus to the type of armor or weapon they are using. This would stack so long as the character meets the level requirements (usually I would set it where it can stack at 3rd, 6th, 9th, 12th, and 15th level up to a maximum of +5--just like the DMG). If players don't want to spend their precious feat slots, then you can make these abilities as class abilities (a defense bonus as mentioned in the Unearthed Arcana), or a skill (class skill for fighter types, cross-class skill for other types that for each 3-5 ranks into a skill grants a +1 enhancement bonus to a particular armor or weapon. This will create a range of +1 as low at 1st level for fighter type characters to as high as +7 or +4 at 20th level for those same fighter types (half that for the non-fighter types).
To illustrate the example, let's do a normal comparison of your standard D&D fighter with magic stuff and a non-magic D&D fighter.
At 20th level, a D&D fighter can buy +5 mithral full plate armor (+13 armor bonus), +5 tower shield (+9 shield bonus), assigned himself a base Dex of 12, but buy gauntlets of Dex +4 (for a total +3 Dex which applies due to the mithral on the full plate armor), wear a ring of protection +5, wear an amulet of natural armor +5, and a dusty rose ioun stone (+1 insight bonus) for a total AC 46. If our same fighter had at least a 13 Int, he can get Combat Expertise feat and increase it up to 51. He'll be a hard target to hit even for a CR 20 creature, but not impossible unless the party cleric throws up prayer and the fighter also opts to fight defensively (effective AC 54). Of course if he's doing this, it's unlikely he's going to hit his opponent as he's already suffering a -2 for the tower shield, -5 for Combat Expertise, -4 for fighting defensively, though the +1 for prayer for a net of -10 to the attack roll in addition to his normal modifiers and BAB. As a lot of monsters in the CR 20 are pushing AC 30+, the fighter may probably get one hit in and just waste his other three attacks, so it's likely he's capped himself out at AC 46 on his own merchandise.
At 20th level with a low-magic campaign, your 20th level D&D fighter gets full plate armor (+8 armor bonus), tower shield (+4 shield bonus), assigns himself a base Dex of 12 (+1 Dex bonus). Now our fighter just has AC 23. To put it in perspective, any monster he fights in the teen range to CR 20 is definitely going to hit him on every attack so long as they don't roll a 1. If our fighter wants to get his AC up, he'll need Combat Expertise (up AC 28), fight defensively (-4, but now he's up to AC 30), and if a comrade wants to offer themselves as an extra target, they can provide an Aid Another to increase his AC to 32, but our fighter is also at -11 to hit the monster. Monsters in the CR 20 can still hit our fighter with a less than 25% miss chance including the roll of natural 1.
So now the DM will want to ask themselves as to what level do they let the magic flow in? If there is no magic and characters have to fight fantastic monsters, they'll die every time at higher levels. Using only magic spells to buff up a character can help depending on as many spells able to get cast before an anticipated combat, but seriously depletes the resources of the party's cleric to provide healing, and at higher levels, it won't make a difference, because the party will get killed off. If the DM creates feats to supplant magical bonuses, fighters are the only combatants who can afford them as such feats likes the ones I've described above will eat virtually every slot for non-fighter types. If the DM creates skills to supplant the magical bonuses, it works better, and some players may want to create more well-rounded charactes with higher Int scores. If the DM goes the Unearthed Arcana optional rules on defense, but with no magic, you're back to square 1 in that your player character will lose every time. Lastly, you can figure in a class ability for each character class you allow, but that involves work on the DM's part (but changing any system to make logical, consistent, and mechanically sound changes involves a lot of work).
Me, I like the high-powered magical campaign settings myself. D&D is built for it. I'd only run low-magic campaign settings for low-level campaigns (like historical games which could be interesting), but everyone has their own preference based on time, role-playing, and the headaches involved in DMing. I know a lot of DM's run low-magic campaigns to force their players to role-play out every encounter (I had a DM who wanted us to talk to every monster we encountered-some sessions we never rolled dice) or to make their game more grimmer and dark. That's fine if your players are game for that, but if you have a bunch of hack-n-slash Knights-of-the-Dinner-Table types, it's more rewarding to give them what they want than to force feed them into playing styles that they don't bring to the game. We revolted against that one DM who wanted us to role-play out every encounter and asked him to leave after a few sessions. We just weren't the type for his campaign. Oh well. Good luck with your customizations!
