Interesting point, but if Bethesda were going to consistently apply that reasoning, then you might argue that they should also exclude axes/maces, since there isn't much you can do with them besides swing from one side of your body to the other....
Of course, there are arguments to be made that there's more to be done with an axe/mace. Put a spike on top and you can thrust with them to do damage. But similarly, you could imagine someone flicking the butt of a spear in a circular motion to do damage.
Very true but generally a side-to-side motion of an axe is more interesting and fluent than a thrust. But you're correct... To be honest, I would love if they added 1-handed spears with the only offensive technique is a thrust or joust. It gives more meaning to use the spear over another weapon, and vice versa gives you reason to drop the spear and pull out that sword in your sheath(similar logic behind the improved bow, sometimes you either have to retreat away or drop the bow and pull out a sword) Just like magic there are now positives and negatives to using a certain weapon.
Or as you said, if the spear is 2-handed then there are more options. Swing the butt of the sword around like a staff and do some Chinese-like fighting. Which is also fine with me. I'd prefer the 1-handed spear and shield combo but I likely won't use it too often so I'm cool with either.
The likely candidates for polearms include: halberd, glaive, danish axe(appears to be the style "the executioner" wields), and the non-bladed staves. Which are all the 2-handed style, instead of the 1-handed greek/roman typical spear.