I’ve cooked up some substantial house rules for D&D 2nd Edition, but if you play a different retroclone or other OSR (old-school Renaissance) game that maintains the old ways, there’s a pretty easy way to improve the martial-caster divide. That is, there’s a way to give martial classes more tactical decisions in combat and to reduce the power gap between fighters, paladins, and rangers versus mages and clerics that starts at mid levels.

Melee Tactics

Start by giving the martial classes something to do in combat other than hitting with a melee weapon or using a ranged weapon.

• Standard: You do full damage and, if your opponent doesn’t hit you for damage and is the same size or smaller, shove the opponent 5′ back or to one side.
• Sweep: You do half damage to up to 3 creatures with one attack roll, as long as it hits their AC and you move at least 10 feet in doing so.
• Target: You do half damage but hit a specific body part (such as the hand) that is not typically a target (like the head).
• Spoil: You do half damage but spoil an opponent’s next attack or attempt to chase you by throwing sand or dirt, knocking over barrels, toppling a brazier, etc.

Restrict attacks of opportunity to situations where the character is prone.

Now melees won’t be a static trading of blows. Note that allowing sweep attacks also makes rogues as well as clerics more useful in melee.

I’ve added other things to melee to make it more tactical and cinematic, like weapon effects, daring feats, and hand-to-hand maneuvers, but we’re keeping it simple here.

Fighters, Paladins, & Rangers

Then, we can give martial classes a couple of features that develop their attacks into something heroic, instead of just more hack-and-slash at higher levels. We’ll borrow a bit from 5th Edition as well as 4th Edition Dungeons & Dragons.

• At 4th level, martials get “1.5” melee attacks; this is 1 attack as normal and 1 at disadvantage (the 5e mechanism). At 7th level, martials get 2 attacks; at 10th, 2.5; at 13th, 3.
• At 5th level, martials can treat 1 hd creatures as if they had 1 hp (minions from 4e). At 8th level, martials treat 2 hd creatures as minions; at 11th, 3 hd; at 14th, 4 hd.

Therefore, at 5th level, a fighter can cut down up to 3 orcs with each of 2 attacks (one at disadvantage), while moving 10 feet each time. That’s 6 (possible) kills by moving 20 feet. And that rises to 9 kills of bugbears at 11th level. That makes a high-level hero a whirlwind of destruction against mooks.

This should give warrior characters more meaningful choices in combat and the ability to take out more low-level characters per round, like higher-level wizard.

Now… big monsters can use sweep attacks and forced movement against the PCs, too. And this distributes some of their brutal damage across more of the party, which avoids one fighter being taken down to single-digit hit points while the rest of the party hurls missiles and insults.

Lastly, don’t be shy about giving fighters magic weapons other other items that make them powerful. A high-level fighter should be able to fly or resist magic or charge thru walls due to magic items.

Wizards

As traditionally played, wizards tend to rely on damage-dealing spells for two reasons: they have to choose the spells they can cast at the beginning of each day, and there are spells that do good damage. Adventurers get into a lot of fights, so it makes sense that PCs would nearly always choose doing damage over water breathing or levitation.

You can fix that in three ways:

1. Make sure there are just as many puzzles and predicaments as there are combats, so they’ll use spells to solve problems, not just blast monsters.
2. Allow them to cast one or (at higher levels) two 2nd- or 3rd-level spells a day without needing to memorize them. This should encourage them to use more utility spells and fewer combat spells.
3. If you’re playing D&D 5e, make all spells one level higher. Cantrips are now just showy smoke puffs and minor illusions and such (the effects of 5e prestidigitation and thaumaturgy). The former 9th-level spells are now “legendary” spells available only to legendary wizards (NPCs). Casting a 9th-level or legendary spell requires you to roll 1d20; if you roll a natural 1, the spell’s power causes you to lose 1 point of wisdom permanently. This explains the existence of crazy funhouse dungeons: eccentric wizards start building a dungeon using powerful spells, which make them more eccentric, and eventually they’re crazy and so is their dungeon.
4. Avoid giving wizards much in the way of magic items. Magic items are created by wizards for other characters. Sure, one could eventually have a bag of holding or other innocuous (non-combat) item, but stay away from staffs and wands that just reproduce spell effects the wizard already has.

Rogues

Rogues tend to get left out of the martial-caster debate, but they have a lot of the same problems as martial characters.

In my house rules, I have a small set of features for rogues that allow them do amazing things as they rise in level, such as perform a coup de grâce, evade big blows, and charm people almost magically with their fast talk and flattery.

But you can just say at 6th level, rogues can treat 1 hd creatures as if they had 1 hp. At 9th, 2 hd; at 12th, 3 hd; at 16th, 4 hd.

And, like fighters, rogues should get nice magic items as they reach mid- to higher levels. A thief should have a cloak of elvenkind or a dagger of silence or an amulet of armor.

Clerics, Druids, & Monks

Clerics, druids, and monks are are pretty nicely balanced in most games. They tend to fall in the middle of martials, who fail to grow into great heroes, and wizards, who quickly grow into genies who slaughter hordes and bend space and time.

So just say at 6th level, they can treat 1 hd creatures as if they had 1 hp. At 9th, 2 hd; at 12th, 3 hd.

These sorts of characters should eventually get more magic items than wizards, but not much more. And avoid duplicating the effects of magic they already wield, and instead give them items that give them different capabilities.