I didn't do the change but it was probably done because the model looks too heavy and long for 1hand use (that's what she said btw). I like the change to be honest. A RL awlpike is a dedicated 2h weapon if I am not mistakes and quite some people facepalmed when TW introduced it with shield use back in beta.
This.
The awlpike is still long enough for people who want a touch more reach then the warspear, and is still usable with shield (with penalty). For spear + shield people, there is the warspear, no penalty with shield, quite effective stab (especially when heirloomed), and a usable weapon in 2h mode, as well (especially when heirloomed).
While spear+shield isn't exactly a dominating class... it still doesn't mean they need fantasy weapons to make them better.