They died because the maps were not properly integrated into MM. They should have dropped directly into MM from the start, forget getting to know them. The MM system could have operated just as in H3 and not made them available to parties that had someone who did not have them. That worked fine. They could have always had a separate area for players to play just the DLC. Hind sight is 20/20, but having had a system that puts new maps into play for general MM was easy enough to do it earlier. Besides, the system infrequently offered them for Snipes, Objective and others types that would benefit by playing on them.