Long time lurker here and first post but I have followed this thread with interest. Although, I haven't played enough of the demo yet to pass judgement on the effectiveness of mortars, I will make some comments based on my experiences as a Company Fire Support Officer for the 1-13 Armor out of Fort Riley and as a Battery and Battalion Fire Direction Officer for a Self-Propelled (M109A5/A6) unit and Light Towed (M102A2) unit.
My experience with mortars (107mm) has been that wind speed plays a huge part in mortar effectiveness. On the open and windy plains of Kansas, the 107mm Mortars w