Whilst I don't pretend to be anything more than a layman regarding history, I do know that Dark Age Northern European armies, particularly Anglo Saxon and Scandinavians (Norse/Danish etc) used a variety of spears, as missiles and as melee combat weapons. As opposing Shieldwalls closed, they would launch volleys of missiles (stones, spears, axes, slingshots, bows and anything else that comes in handy). Then when the Shieldwalls came together and combat began, they would switch to larger spears intended for melee. Warriors would often carry several spears of both types.

Given that the Rohirrim are heavily inspired by Anglo Saxon and Scandinavian history, I think that Rohan Spears should count as both a throwing weapon and a standard spear, though not in the same turn. The points cost should remain the same at 2pts, or be increased to 3pts.

Theres a number of instances in the LOTR books and Unfinished Tales when the Rohirrim are specifically described as fighting in shieldwalls, much like the Anglo Saxons and Vikings. IMO a Rohan player should actually be able to do this in game.

_________________
My (more regularly updated) painting blog:
https://www.facebook.com/Pindergorn/