Nuka World
Nuka World is a flawed DLC despite how much I love it for the fact that it was optimized for an "evil" playthrough and doesn't provide much in the way of those who prefer to take their Fallout deadly serious. It, however, is quite possibly one of my all time favorite additions to Fallout overall, though.
This has put me in an awkward position with many of my fellow gamers here on the forums, though, because they can only see the flaws of it and outright hate Nuka World. They think of it as symbolic of Bethesda's dislike for the franchise. Quite the contrary, I see Nuka World as what Bethesda should have been doing with Fallout from the very beginning. Squirt gun and all.
Why do I like it so much?
On a basic level, Nuka World embraces being imaginative and colorful versus the fact Fallout 4 was almost uniformly a dull shade of green. There was very little worth exploring in Fallout 4 with the exception of Diamond City, the Glowing Sea, and the Institute. For a game which is meant to be a exploration simulator, this is a fatal flaw.
Nuka World at the very least, even minus all of the Raider plans, is a game which allows you to go look through new and exciting locations which contain more interesting things to look at and explore than the entirety of the rest of the game. There's jungles, zoos, kiddie rides, haunted houses, a simulation of Space Mountain, a Vault-Tech facility which recanonizes the Enclave's plans to colonize space from Van Buren (or at least hints at it strongly), a Nuka Cola factory, and numerous cases where you can actually talk your way down.
Part of what I love about Nuka World is it's a return of Fallout's sense of whimsy and humor, which was almost completely absent from the main game. It's a bizzare and silly place which includes homages to Fallout 2 (Hubologists!) as well as a few obscure in-jokes like the Winchester Mystery Mansion (which is a real place).
I think your love of Nuka World may be affected by your love of Disneylore as the amount of injokes ranging from the Epoct Center boat ride to Space Mountain to the Hidden Mickeys all made me laugh my ass off. As mentioned, I got the Grandchester Mystery Mansion reference as well as the Lizzie Borden's jokes. The return of the Hubologists was also a welcome one as I've always loved that group and regretted the fact they never got a happy ending.
The amount of CHEER in the game is just overwhelming with Dry Rock Gulch including things like giddyup buttercup round-ups, the ability to appear as the Siilver Shroud, and a return of Sierra Petrovita! Oh, how I've missed her so much! She was probably my favorite of the returnees in Fallout 3, even more than Arthur Maxson.
Plus, I love Coca-Cola and Cola-Cola merchandise in the real world.
But what about the Raiders? Well, I'll be honest, Raiders have always been one of my favorite elements of the Bethesda fallout series. I've never been happy with the fact the first two games have ignored them for things like the Enclave and Master. I always wanted Lord Humungous to be one of the big threats you faced and they've only ever been reduced to sidequests--a fact which Fallout 3 and New Vegas both continued. For me, it was a dream come true to finally be able to become the King of the Raiders and rule from an Iron Throne with Piper and Cait at your side.
It's nice also to be able to decorate your home Raider style without Moira Brown to JUDGE you for it.
Seriously, is there anything more dedicated to PURE FUN than post-apocalypse Disneyland?