But just because they have one polearm doesn't mean we will see the many different types, including spears. Also, since in Morrowind halberds were governed by the spear skill, the idea that the weapon in the picture might be governed by the axe skill (or two-handed, w/e) makes a big difference.
I'm not sure I see the relevance of which skill that weapon will be governed by... After all, longswords and axes will both be governed by the one-handed skill, but those are clearly different weapons.
If halberds are in, what will presumably distinguish them from two-handed axes are (1) skill perks, and (2) animation (axes will chop, halberds will thrust).