Whenever this topic has come up in the past there have always been people who argued against polearms, either on the basis that they are only suited for formation warfare, or that they are peasant weapons not suited for the player character. I haven't really seen anyone go that way in this thread yet, but since both aspects were touched on I thought I'd address it before someone takes it a step further.
While polearms are no doubt excellent weapons in formation warfare, its a bit of a myth that they are useless in solo combat. The Samurai fought with polearms both in pitched battles and in duels, and the Norse sagas also recount tales of Vikings fighting and killing each other with spears in duels. There were also a few different types of gladiator who fought with polearms. One of the fan favorites of the Romans' was the Retiarius, a man who fought unarmored and with a long trident and a net. There was also the Hoplomachus, who was armed with a spear, buckler, and dagger.
Reenactors depicting a fight between a Hoplomachus and a Mirmillo. (short sword and shield)
Fencing - Spear vs Sword & BucklerPoleaxe tactics - European Martial ArtsPolearms are no less viable in solo combat.
While it is understandable at least that a person who wrongly believes that polearms are unsuitable for solo combat would be against their inclusion, the argument against their inclusion on the basis that they were 'peasant weapons' is a difficult one to understand. So were axes, scythes, clubs, and maces...all weapons commonly found in RPGs, and weapons I've never heard anyone ask to be removed from a game. And in any event it is also a bit of a myth that they were exclusively peasant weapons. While their cheaper and easier production made them common weapons for the lower classes, they weren't exclusively weapons of the lower classes. The nobles and warrior classes amongst the Vikings also fought with polearms quite frequently. So did knights and so did the Samurai. The difference between a noble and a peasant was mainly that the noble likely could afford to also own a sword to fall back on if his polearm was lost or damaged.
The argument that they'd require an additional set of animations, and thus might not be worth the time and resources, could be a valid one though. It all depends on where development time and resources are being spent. The inclusion of polearms and additional animations may require some other aspect of the game ending up cut. Whether or not that trade off would be worthwhile off course depends on what would need to be cut.