As it stands, the future of the Fallout franchise remains uncertain. The only real comment about a new game after Fallout 76 was a statement that Fallout 5 would be a single-player experience, whenever it manifested. Yet, one fan demand has always been a follow-up to Fallout: New Vegas instead of a new numbered entry, but this has always been highly unlikely.
Now, with Microsoft's acquisition of Bethesda being finalized this coming year, there's more possible than ever before. Microsoft, Bethesda, and Obsidian Entertainment have the opportunity to make Fallout: New Vegas 2 a reality, but there's another possibility that has been passed through circles before. Not only would it be great to see "New Vegas 2" actually being Fallout: New Orleans, but the solidification of that identity would come from stepping into the boots of another Courier.
Fallout: New Vegas 2 vs. Fallout: New Orleans
There's a lot of reasons New Orleans would be a good spiritual successor to New Vegas, and a spiritual sequel seems better than a direct sequel. New Vegas 2 taking place in the Mojave Wasteland would not only have the daunting task of following the original, but it would also have to deal with the variety of endings.
At best, this would likely undermine the Fallout: New Vegas Courier to some degree, but on the flip side, that identity is important. There's also the fact that the mainline games, which a "sub-franchise" wouldn't necessarily have to follow, have never been direct sequels. They are connected, but Fallout 4 did not take place right after Fallout 3, obviously. In other words, should Bethesda lend Obsidian the IP once again, it would likely need to find a new road to being a "sub-franchise."
Fallout: New Orleans was something that "leaked" many years ago, though these leaks were unfounded. Nonetheless, the very idea of a Fallout: New Vegas-style game taking place in the Big Easy is undeniably intriguing, having lasted in the hopes and dreams of many ever since. "New Orleans" sets up the perfect naming convention continuation all the same; if continued by Obsidian and not being a numbered entry, it would only make sense for the legacy to continue by having subtitles with the word "new" in them.
The Identity of a New Vegas Sub-Franchise
However, it takes more than just naming conventions to define a franchise or spin-off of said franchise. Again, there's a lot of reasons New Orleans is perfect to follow New Vegas, but there's one thing that has to be included to maintain this identity: a Courier. Looking at the identity of the protagonist in the mainline games makes this obvious enough: in Fallout 1, players were The Vault Dweller (which carried on); in Fallout 2, players were The Chosen One; in Fallout 3, it was The Lone Wanderer; and in Fallout 4, it was the Sole Survivor.
The Vault Dweller carrying on was important as, while each character had this identity, they were all part of this Fallout Vault system. In the latter three, there's a formula of something embarking a lonely feeling, with a solemn adjective accompanied by a character-determining noun, which is not as complex as it seems. Essentially, every character in a mainline Fallout game was a Vault Dweller generally while specifically something else. In Fallout: New Vegas, the players are specifically Courier 6, but a New Orleans game could establish a new name but maintain the Courier role.
Ultimately, there's nothing written in stone and it seems like a pipe dream. It may very well be, but a new Courier in New Orleans in a new Fallout game is a good dream indeed.
A new Fallout game is not confirmed to be in development.