Generally, open-world games with a large variety of dialogue, quest and storyline options often result in an overall lackluster plot. Skyrim was a great example of this. The storyline is, overall, shallow and your actions feel largely meaningless. Siding with one army or another merely changed which uniform you would see on the guards within towns and effect a few quests. It was all lacking any real depth. However, with all the DLC install, the storyline for New Vegas feels very complete and actually has quite a bit of depth. Friends of mine complained, but I merely say that, firstly, they played it without the DLC installed (Lonesome Road offers a great perspective on everything, I feel) and that they weren't thinking enough to realise what it all meant.
What I am worried is that, with Fallout 4 likely being made by Bethesda Game Studios (as with Fallout 3) and not Obsidian, is that the plot will subsequently become lackluster a la Skyrim. What do you think? Leave your opinions below!