Wasn't it the Warhammer RPG that had all weapons do the same damage?
For D&D purposes, they are close enough to make no difference, but you could allow for different stunts with them, if you're inclined that way. For example, the glaive is a better choice for cutting the rope on the chandelier, while the halberd can be used to push or pull something at distance better.
Wasn't it the Warhammer RPG that had all weapons do the same damage?
Yes, I know there really IS a difference - but in my 5e PH, both are listed with identical stats... cost 20 GP, 1d10 Slashing, weight 6 ibs, Heavy, Reach, Two-handed. Why? Is this a mistake?
Glaive
A glaive has reach. You can strike opponents 10 feet away with it, but you can’t use it against an adjacent foe.
Guisarme
A guisarme has reach. You can strike opponents 10 feet away with it, but you can’t use it against an adjacent foe.
You can also use it to make trip attacks. If you are tripped during your own trip attempt, you can drop the guisarme to avoid being tripped.
Halberd
If you use a ready action to set a halberd against a charge, you deal double damage on a successful hit against a charging character.
You can use a halberd to make trip attacks. If you are tripped during your own trip attempt, you can drop the halberd to avoid being tripped.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.