The Wandering Gamist long ago discussed the problem with classic Dwarves in B/X and derivative games, that essentially they’re a Fighter with better saves for a slightly increased XP cost. He ended up proposing some adjustments, and more for the classic Elf as well.
I certainly agree on this issue and have often cautioned against similar cases of niche-encroachment on the ACKS Discord, but thus far my solution has been to modify reaction rolls based on race and ethnicity. That works in terms of the broader game and incentivizing human characters, but fails to leave the redoubtable human fighter with his own unique role in adventuring as the master of versatility.
To that end, I have put together variations on the Elven Spellsword and Dwarven Vaultguard, that I think valuably focus those classes and narrow them.
Variant Spellsword
Key Attributes: STR, INT
Requirements: None
HD: d6
Max Level: 10
XP to 2nd Level: 4250
Combat Proficiencies: Spellswords have weapon proficiency with all swords and polearms, and with missile weapons. They have armor proficiency with medium, light, and very light armor. They have fighting style proficiency with all three optional styles (i.e. the dual weapon, two-handed weapon, and weapon and shield styles).
Combat Progression: Like fighters, spellswords advance in attack throws and saving throws by two points every three levels of experience. They increase their base damage roll from successful missile and melee attacks by +1 at 1st level and by an additional +1 at 3rd, 6th, 9th, and 12th level. They can cleave after killing a foe a maximum of once per round per class level.
Starting Class Powers
At the start of play, spellswords have the following class powers: Arcane Magic (as a Mage), Collegiate Wizardry, Natural Stealth, and Wakefulness.
Additional Class Powers
When they advance in level, spellswords gain the following additional class powers: at 5th level, they gain Minor Magical Research; at 9th level, they gain Major Magical Research and can found a Fastness.
Racial Traits
As elves, spellswords have certain powers associated with their race: Attunement to Nature, Connection to Nature, Elf Tongues, Longeval.
Class Proficiencies
Proficiency Progression: At 1st level, spellswords select one class proficiency from their class proficiency list and one general proficiency from the general proficiency list. They select an additional class proficiency at 3rd, 6th, and 9th level. They select an additional general proficiency at 5th and 9th level.
Spellsword Proficiency List: Armor Training, Battle Magic, Beast Friendship, Black Lore of Zahar, Blind Fighting, Combat Reflexes, Combat Trickery (disarm, knock down), Command, Counterspelling, Elementalism, Expanded Repertoire, Experimenting, Familiar, Fighting Style Specialization, Loremastery, Magical Engineering, Magical Music, Mastery of Enchantments & Illusions, Mounted Combat, Mystic Aura, Quiet Magic, Precise Shooting, Prestidigitation, Running, Sensing Power, Skirmishing, Swashbuckling, Transmogrification, Unflappable Casting, Weapon Focus, Weapon Finesse
Secrets
The variant spellsword is built as HD1/F2/A1/E3, the same as the classic spellsword. It trades weapons down to Broad and Armor down to Broad, gaining 2 class powers and increasing the base XP to 2nd level by 250, for a total of 4250 XP to 2nd.
Variant Vaultguard
Key Attribute: STR
Requirements: CON 9
HD: d8
Max Level: 12
XP to 2nd Level: 2650
Combat Proficiencies: Vaultguards have weapon proficiency with all axes, flails, hammers, and maces, and with arbalests, crossbows, javelins, spears, polearms, and arbalests. They have armor proficiency with all armor. They have fighting style proficiency with the two-handed weapon and weapon and shield styles, but not with the dual-weapon style.
Combat Progression: Like fighters, vaultguards advance in attack throws and saving throws by two points every three levels of experience. They increase their base damage roll from successful melee attacks by +1 at 1st level and by an additional +1 at 3rd, 6th, 9th, and 12th level. They can cleave after killing a foe a maximum of once per round per class level.
Starting Class Powers
At the start of play, vaultguards have the following class powers: Attention to Detail (+1), Dungeon Bashing, Labor (any), Manual of Arms, Tenacity, and Weapon Focus (any one).
Tenacity (New Custom Power): Vaultguards do not forsake their oaths of warding lightly, even when foes strike them down near unto death. Upon reaching 0 hit points, the vaultguard can choose to remain in fighting condition, functioning as if he has above-zero hit points but only able to take a combat action each round. He continues to apply any further damage as normal. He can continue fighting until he reaches a negative number of hit points equal or exceeding his Constitution score, until he stays conscious for a number of rounds equal to his level of experience, or until he chooses to yield, at which time he becomes incapacitated as normal. He then suffers the price of his stoicism, taking a -1 penalty to his Mortal Wounds roll per round of fighting past 0 hp. (This is a modified version of the Martyrdom power from the Flagellant class in Axioms 10.)
Additional Class Powers
When they advance in level, vaultguards gain the following additional class powers: at 5th level, they gain Battlefield Prowess; at 9th level, they can found a Vault.
Racial Traits
As dwarves, vaultguards have certain powers and drawbacks associated with their race: Dwarf Tongues, Hardy, Sensitivity to Rock and Stone.
Class Proficiencies
Proficiency Progression: At 1st level, vaultguards select one class proficiency from their class proficiency list and one general proficiency from the general proficiency list. They select an additional class proficiency at 3rd, 6th, and 9th level. They select an additional general proficiency at 5th and 9th level.
Vaultguard Proficiency List: Alertness, Berserkergang, Blind Fighting, Caving, Combat Ferocity, Combat Reflexes, Combat Trickery (force back, knock down, overrun, sunder, wrestling), Command, Dwarven Brewing, Fighting Style Specialization, Goblin-Slaying, Illusion Resistance, Intimidation, Land Surveying, Leadership, Martial Training, Military Strategy, Mountaineering, Precise Shooting, Prospecting, Running, Siege Engineering, Unarmed Fighting, Vermin-Slaying, Weapon Focus
Secrets
The variant vaultguard is built as HD2/F2/D1, as the classic vaultguard but with more dwarf in the mix. It trades weapons down to Broad and trades away the dual-weapon fighting style and ranged damage bonus, gaining 3 class powers and increasing the base XP to 2nd level by 250, for a total of 2650 XP to 2nd.
Further Variations
Some other thoughts have presented themselves as ways to modify the above classes yet further. The most straightforward would be to add Inhumanity to each race, not affecting their XP costs. This would grant elves a +1 bonus to reactions, loyalty, and morale with other elves, but impose a -1 penalty to such with humans and a -2 penalty with dwarves. Dwarves would of course reverse that, gaining a +1 bonus with fellow dwarves, a -1 penalty with humans, and a -2 penalty with elves.
A yet further variation on the vaultguard might represent more of a barbarian-type hill dwarf, dropping heavy armor proficiency and gaining Savage Resilience. I think the overlap with a human barbarian there would be small; losing Natural Stealth and Animal Reflexes changes the character of the archetype considerably, and the dwarf talents above emphasize more the modern berserker-barbarian role (particularly if one took Berserkergang at 1st).
For a more urban take on the spellsword, my thought tends towards replacing Natural Stealth with Magical Engineering or possibly Loremastery, to reflect a lifetime of experience to draw upon. Magical Engineering would also nicely boost their magic research back on par with a Mage of their XP.
My apologies that my posting has been lax of late; getting another round of edits put together for ACKS II has dominated much of my time lately, but now I have a brief break and a number of articles I’m looking to get turned around quickly to make up for that. Most notably, Birthright!
Commenting on BX rather than ACKS, but the Dwarf niche originally is dungeon detection, surely?
Can you please elaborate what did you change there from ACKS II? On first glance, it seems that you've created another boon for those classes, making them even better in their own niches. How does that solve the fighter being obsolete? I can see the XP cost increase as a possible answer but I'm afraid I didn't understand what you were trying to achieve...