I don't think you would find much disagreement here.
I liked how FNV continued the West coast and NCR's storylines but know that we know how that has turned out I wouldn't mind seeing a Fallout game set in a different locale with different factions (though I don't mind if Ghouls and some Super Mutants showed up, some, not an army), governments and so on.
I was playing myself with a concept I call Fallout Texas which takes place in that state.
A few elements from the West coast and previous games could show up such as the Caesar's Legion that is responsible for a lot of destruction and chaos before the start of the game, a Ghoul who may or may not be a NCR Ranger, and some Super Mutants that were former Legion slaves (or immigrated to the Texas Wasteland before the Legion arrived), but for the rest new faces
Rather than unified or being unified under one government there would have been powerful city states/nations such as the Lone Star Confederacy which bases its origins in the Confederate States of America (but with Fallout twists) and the System, Post Nuclear communism founded by Chinese POWs who intermingled with locals, who compete with each other for the hearts and minds of the people.
There was also San Antonio, an emerging city state that was founded with help of the New Texas Rangers before it got wiped out by the Legion.
There would also have been a clash between science and religion; the Followers of the ATLANTIS, a para military transhumanist organization composed of cyborgs that are led by an Artificial Intelligence who believe that instead of rebuilding the world in the old image that humanity should move on. (unlike the Brotherhood of Steel they deal and trade in technology, and almost everything is for sale as long as people can pay it, only things they don't sell are weapons of mass destruction)
And the Angels of the Apocalypse, a warped military Christian organization who wish to unite every under one faith and cleanse the world of science and technology.
And last there would be a clash between Law and Order and organized crime/right of the strongest; the New Texas Rangers who like their Desert Rangers counterparts wish to bring order and safety to the wasteland, and the Black Fist, a crime cartel that seeks to benefit from the re emerging civilization by providing alcohol, drugs, gambling, and prostitution, and is involved in matters such as gun running and racketeering. (interesting enough the Black Fist does keep raiders and slavers in check)
And there would have been 'forbidden' locations such as the Corpse, the ruins of Corpus Christi that are now being overgrown by a toxic mutant jungle (the Bloom), and Robot City, a futuristic 'city of tomorrow' that is built on the ruins of Austin and inhabited by machine intelligences that wish to remain isolated from the rest of the wasteland.