I think the number of the weapons and little meshes would increase very quickly if some developpers gives the right to modify a weapon (by modifying an existing weapon people could be able to create a new model).
Off course I know there is a ps licence and I don\'t wanna change it but I think a developper could write a little sentence to explain if he is ok to let people modify his arts. The ps licence would be respected cause the dev would keep his rights and a new dev will be allowed to work on his arts (it must be to help the ps community off course).