I've seen a lot of people complain about a lack of quests in Fallout 4 as compared to other Bethesda games, and I've come to realize....
Bethesda brought back that uncertain exploration feeling. There are fewer instances of "go here, do this", and plenty of "I just found a mannequin with it's hand pointing north. Wonder what's up there?"
Unmarked quests were a hallmark of Morrowind and other earlier RPGs, and you were forced to think your way through quests and locations. Fallout 4 has more of this than Oblivion, FO3, or Skyrim did (though each had a few), and in over 200 hours, I still haven't run out of things to do.
For all that the main quest is underwhelming, the world of the Commonwealth was done right. Thank you, Bethesda!