I think that it will never be added to the game.
I remember the answer that RETO made about bipode : problem with the floor, small walls and fences (using bipode behind a cover) and the mechanics of the characters.
The solution would be that the mortar could not be deployed evrywhere.
Maybe, a mortar need a litle rectangle of flat map flor to be deployed, This is still a piece of artillery even if it is small.
It could ruin the game if it was too eficient (battlefield ww1). It should be limited to a RDG33 in term of blast, not accurate or quick anought to block a street and the range should not permit to be totaly out of reach of rushers. (time needed to pack it up and run the f°ck away with a jeep)
It is possible to add it without modificaions of the existing maps. They would have to create a new animation for the soldier feeding the mortar, wich is long, and obviously, a balistic for it. You know what guys ? they could make it ezz, but they already fear your "feed back" sugestions about range, rate, power...