I didn't like that either. After I was done with the main quest, I had barely seen any of the areas on the map, and I only had maybe half a dozen side quests queued up to do at that point. The older games did a much better job of presenting side quests and areas; as I've seen others mention, it was much more common to find a note or NPC or something that would lead you into a much larger storyline, whereas in FO4 most seem to just present lore. Even a 'we're at a dead end, go do other stuff for awhile' type of thing, a la Caius in Morrowind, would have been welcome in my opinion.