To be fair, DLC seems to be where Bethesda shine.
Fallout 3, while enjoyable, lacked anything which made the originals good. But the DLC at least brought back some of that atmosphere (which pains me as to why they left that out of F4, Bethesda knew what they were doing with that game but... that's a rant for another time).
So I'm kind of hoping that Fallout 4 has DLC that outshines the main game.
The problem Bethesda has, outside of Morrowind, they aren't good at telling big stories, but they can write smaller, more personal stories pretty well. Some of the locations in F3 and even F4 which don't have any significance but are just there to tell a story not related to anything except the game's world, are pretty good. And they bring more to the world than the main story ever did.
The main story of Fallout 3 was pretty dry. There was no real depth, it was just "bring down the big evil and watch your father die for no reason" which sucks. But then when traveling the Wastes, you find a radio of a guy from the pre-war telling us about how him and his family are hiding in a sewer to look after their ill son. You find the source and see three skeletons on the floor.
Telling a story with showing the player the conclusion is a unique form of writing. I wish Bethesda would do more of this. There were some strong parts of Fallout 4 I admit with the Kellogg's history.
It's a shame that Bethesda prefers sales other writing a decent story. It actually doesn't make sense. New Vegas proved that you can make a good game, sell well and get good reviews. But people would rather collect power armour pieces than develop a decent story.
The amount of people who prefer New Vegas over 4 (and the amount of people who say Obsidian ruined Fallout for them, in which case I can't help but argue).
So for me, as long as the DLC plays to Bethesda's strengths, I mean The Pitt was a perfect example of showing us a glum World not just through environments, but through people's behaviour, then yes, DLC will save the game.
Otherwise... meh... I wasted £100.