I think they'll definitely remove all gold-generating missions and the possibility to trade ressources for gold directly, but the garrisons need to remain active otherwise future players will never be able to get most of the content of Draenor (achievements, treasure maps, mounts, pets, toys) all exclusive to the garrison missions. Plus I've tried to do invasions and invasion bosses every week since release and I'm still missing one invasion type and haven't seen like 3 of the bosses ever, so that shit needs to stay or people will be angry they missed out on the rare drop mounts and achievs.