while some halberds can be used as spears, that's not how they are primarily wielded.
By definition, all halberds can be used to thrust. From all I know, that is the primary use of the halberd. The axe blade and spike were mainly for taking on opponents who were in a bad position and left an opening for such a slow, but powerful attack.
Thus, spear animations could well be used for all types of polearms that have a pointy end. Add a slash animation to it, and you can also simulate the advantages of those weapons. Two main attack animations for a whole lot of weapons.
Again, the sword. All swords look the same to me. More so than polearms, by far. Yet swords get their own animations.
Also, a spear would not be the sub optimal choice in most fights. Spears have since ages been used for hunting (the boar spear for example), so against all sorts of animals, they are excellent. They also have been used very commonly in warfare, making them excellent weapons against humanoid enemies, given you have enough space to operate. They svck in dense forests and inside buildings, but that's it.
Also: Keep the spear threads coming. Don't spam, but keep expressing that the community wants spears. That way we might at least get a DLC pack with spears at some point. How would they know we want them if we wouldn't have kept telling them?