Well if we're looking to set up a new settlement, the large-ness of a shopping center seems like a great idea. Plus there could be a few cool quests to go around that, setting up power, finding suitable water, picking a store to live in, exploring the parking garage underground, remodeling, etc. Could be really fun! Maybe we go to the drive in theater, hunt the thing, see the mall and think "Paradise!" but discover that there is a feral-ghoul hideout that is spilling into the mall. We soon find out that the underground garage is connected to a motel full of ghouls? Fit everyone's idea into it?