I had an idea for a new DLC and, fates willing, Bethesda will take interest in it. Per Bethesda Support, they apparently have no way for people to submit concepts and ideas for new content or games other than the public forums, I'm forced to post it here.
The DLC concept:
Since there's such a large water area in Fallout 4, I was thinking the Wander could "stumble" across an underwater city that is unaware of any of the changes to the
outside world... other than they ended up getting sealed in and lost communication to Topside.
Since then, they've had to fend for themselves, have developed some aquatic "farming" techniques and water purification processes.
They've also lost a few remote PODs (i.e. Neighborhoods/Developments) to failed domes & seals so there would be a few areas to explore with a rebreather.
Some of the lost PODs would have Ghouls and other nasties awaiting the unaware explorer.
Possibly a few interesting weapons could be added
Would involve adding Voiced dialogue for new characters so several voice actors would be needed.
Their Society would still be reminiscent of the 1950's, with some evolution past that.
During the past few hundred years, they've had to adapt and with some of the domes collapsed, the would have lost access to some resources.
Just a thought... but it would be nice to see it incorporated as a new DLC.
I'd just wait till the new GECK was released and develop it as a Mod but I'm already knee deep in developing a new game with the UE4 engine so I don't have the time.
I'm sure some will like this concept, others will hate it... it is what it is.