Otdfbt

According to the rules, at the end of a fall, a creature takes 1d6 bludgeoning damage for every 10 feet it fell, to a maximum of 20d6.

However, way back in Dragon Magazine #69, D&D co-creator Gary Gygax explained that the original intention was to apply 1d6 damage per ten feet fallen, cumulative. So, a creature would take the following damage according to the distance fallen:

• 10 ft: 1d6


• 20 ft: 3d6


• 30 ft: 6d6


• 40 ft: 10d6


• 50 ft: 15d6


• 60 ft+: 20d6 (max)

If this method of applying falling damage were used in 5e, what (if any) would be the game balance implications? Would it make certain low-level spells overly powerful, for instance?

There are a few implications but most of them are just aggravating already existing factors.

1. Positioning will become even more relevant.

Positioning is already relevant but when a fall causes even more damage some risky places become deadly places. The fall from the top of a 40ft. rampart that caused 4d6 now causes 10d6 damage, what could hurt your character after a shove now can kill him. Every edge from a high place becomes even more important to not get close to it or more rewarding to use offensively.

2. Feather Fall just became more necessary.

Feather Fall already is one of those spells that you always want to have because you never know. A 6th level wizard that was just worried to be throw down 60ft after flying now should be terrified of the idea; he might survive 6d6 but hardly would upon receiving 20d6 damage.

3. People that can avoid falling damage got comparatively more mobility.

You're chasing a 4th level bard and he jumps of a 50ft building, cast Feather Fall and safely reaches the ground. A Fighter or Barbarian might be able shrug 5d6 and keep the chase but even a monk with Slow Fall would think twice in jumping down when the damage is 15d6, ignoring 20 damage, the average of 15d6 still would result in 32,5 damage. The same monk could jump into an existing ledge 10ft under and then to the ground and probably get off with 15 damage, but his companions can't easily follow unless they slowly climb down or have the similar resources.

4. Athletics and Acrobatics became even better skills.

They still aren't Perception, but one of them reduce falling damage and the other helps you to climb up or down and not fall. When falling damage just got lethal, not receiving it becomes more important them before, raising the value of those skills.

5. Spells that can throw you instead of direct damage got a lot more lethal.

Telekinesis, Reverse Gravity and Bigby's Hand can kill a lot more effectively to the point of being almost broken since they can continuously cause 20d6 with a single spell. Beware of those.

The only spells that would have a bad interaction with this are spells that forcibly move an unwilling target and are not restricted to toward/away from the caster, and thus can move targets upwards.

The only spells that come to mind here are Bigby's Hand and Telekinesis.

Bigby's Hand could drop a grappled target from 60ft up, then move down and re-grapple to cause 20d6 (70) damage every other round. Consider that its normal expected damage is 18 per round, and this tactic would approximately double its effectiveness.

Telekinesis has a similar issue, moving a targeted creature 30ft upwards each round and dropping them every second round for a similar 20d6 per two rounds.

The biggest issue here is really that both of those spells are very reliable, as they target Athletics/Acrobatics and Strength instead of AC or Saving throws.

Otherwise, you'll also have to be wary of some grappling character builds - dragging a creature up the side of a building could easily become more damaging than simple attacks at a relatively low level.

For example a level 3 Thief Rogue could attack someone for ~14.5 each round with Sneak Attack.

Or they could grapple and drag them 30ft per round up a building/cliff/etc, dealing approximately 20d6 damage every third round (plus another attack in the middle round), again nearly doubling the expected damage output.

All in all, the two spells mentioned are the most problematic parts as they can be tacked on to many spellcasters, and don't require an unorthodox character build that specifically takes advantage of this houserule.

But consider also that in a world where a 60ft fall is lethal to most spellcasters under level 12, every spellcaster capable of knowing Feather Fall will know Feather Fall, and mitigate the increased danger that way.

The increased danger of falling will have worldbuilding implications. Formerly mundane heights become deadly encounters.

Instant Death (PHB 197):

Massive damage can kill you instantly. When damage reduces you to 0
hit points and there is damage remaining, you die if the remaining
damage equals or exceeds your hit point maximum.

When falling from 40 ft even at full hit points, most low-level characters (pc, from my experience, and npc; DMG 274 for avg hit points for CR X monsters) will outright die. The damage from iconic spells such as fireball pales in comparison to the danger of heights.

Climbing on a tree in the forest may become a deadly encounter. As a DM you will have to be knowledgeable about how tall houses, walls, structures and how high the cliffs of the famous narrow streets between ambush-cliffs are, the mundane life now presents deadly encounters everywhere. Pit traps (DMG 122-123) become deadly. Falling already is a common hazard (PHB 183), any terrain with heights will be more dangerous and treacherous, the odds of someone walking through weather that obscures vision when there is the danger of falls drastically diminishes. A bridge crossing a river at 40 ft is now treated like a bridge that would cross a canyon at 100 ft.

4 hit points Commoners (MM 345) who fall from 20 ft (roughly the roof of a two floor building) and take 3d6 have a 98.5% chance to drop to 0 hit points, if you decide to follow the basic rules recommendations (BR 76) and don't make a death saving throw for most monsters and NPCs this would mean death.

While heights always pose a risk, the cumulative damage now amplifies common dangers to potentially deadly encounters that could easily lead to instant death for low-level characters. You would have to adjust your world-building. The implications are broad, terrains like hills, cliffs, ridges, mountains and tall structures will be more dangerous by default.

Creatures will adjust to a world in which 20 ft falls mean almost certain death for the majority of humans. Expect strategies, ambushes and security measures around heights to be commonplace.