I have been told that having the high ground is historically useful for military units in general but also ranged combatants in particular. I am the DM who has to make this call, but having never shot a person from a tower, I genuinely do not know if high ground is a useful thing for an archer.
Is there any precedent for applying this concept to D&D (or Pathfinder) by granting a circumstantial bonus to a character who is making ranged attacks from high ground (for example, 10 additional feet in elevation compared to the target)? I would like to use this precedent, if it exists, to inform my decision whether or not to grant a character advantage on his or her ranged attacks made from high ground.
A good answer would not only confirm the existence of such a precedent, but would also go into detail about why it makes sense to add such a bonus including information on physics or personal experience with archery.
Best Answer
Is there a precedent for granting a circumstantial bonus to ranged attacks made from high ground in D&D?
Yes.
In 2nd edition it was a +1 bonus. 3rd edition retained this +1 bonus for high ground, though it only applied to melee attacks, not ranged.
Does that mean you should grant a character advantage on his or her ranged attacks made from high ground?
No.
Advantage is significantly better than a +1 or even +2 bonus. Higher ground alone should not be sufficient to grant advantage.
Would it make sense to bring back the old +1 bonus in your 5th edition game?
Probably not.
5e eschewed most static +1 and +2 bonuses (as well as -1 and -2 penalties) in favor of the advantage/disadvantage mechanic. Among other things, this makes it quicker to resolve actions in combat without having to worry about tallying up the individual bonuses and penalties that might apply at a given time.
(Note that 5e does retain the static bonus for cover, which is separate from advantage/disadvantage. So depending on the circumstances you might decide that the character's higher ground takes away the enemy's cover, at least for a round or two. It would depend on the weapon and the type of cover, but it wouldn't be game-breaking as an occasional bone to throw to the party's archer.)
Above all though, reward good play. You could give the character advantage on their first attack from high ground, but afterwards the enemy changes their tactics to account for the threat. Or maybe the character doesn't have advantage yet, but they could spend actions/resources to get to a particularly advantageous location later in the fight. As a DM I've had success using these sort of “No, but...” rulings to create more dynamic encounters, or at least offer the players an alternative to “I hit the thing in front of me.”