Just to present my concept, the general-ish and [b]tentative[/b] one I'd like to try to gun for at least (depending on what is decided for how Fallout 3 ended up here), for the Capital Wasteland before work this evening at least: 

My concept, at least, is that the Lyons' Pride basically kept their gained control over the Capital Wasteland, having split from the main Brotherhood of Steel by the time (and especially after) Maxon took control and initially reduced their numbers a good bit through recruitment and some in-fightning. By this time the Brotherhood Outcasts have either been killed or basically kicked out after rejoining the main Brotherhood body. The Purifier was activated and has been kept secured by a group of Lyons Brotherhood soldiers, as well as being staffed and maintained with the next generation of scientists from Rivet City after Madison Li left. The Enclave has been long ejected from the Capital Wasteland, their Crawler destroyed, and their equipment and gear left behind looted by the Lyons' Pride and kept under lock and key to avoid Maxon getting them as a matter of their existing grudge against the main body of the Brotherhood. 

In the wake of splitting with the main body of the Brotherhood, the Lyons' Pride has become basically a pro-settler order keeper in the Capital Wasteland as they've regenerated their ranks and taken a different direction than the main Brotherhood. They've made it safer, reduced some threats, and basically gotten the area organized overall. Rivet City is thriving and has expanded a bit onto land since the time of the Lone Wanderer. Megaton is intact, but the Lyons' Pride took the bomb from there due to Rivet City needing more nuclear material for their reactor...which caused an internal war with the somewhat more radicalized Children of Atom, who would not agree with that action, that saw them driven out of the Capital Wasteland eventually. Frankly Liberty Prime is not present due to the events of Fallout 4. The ghouls threatening Tenpenny Hotel were wiped out by the Lone Wanderer, but Tenpenny did get forced to capitulate to Lyons' Pride authority after a conflict between their mercs and the encroaching authority of the Lyons' Pride. Three Dog is still running the station. Sarah Lyons leads the Lyons' Pride, and is very much pissed at Maxon and the rest of the mainstream Brotherhood. 

Fawkes remains alive and has been taken into the ranks of the Lyons Pride due to the intervention of the Lone Wanderer, who could be alive, dead, or disappeared by this point, and proves to be an intelligent and helpful aide to the group within the Capital Wasteland. Raven Rock was naturally destroyed. Vault 87 has been for the most part successfully contained, though Little Lamplight's residents had to be evacuated and that settlement was lost (but the cave walled up in turn). The Duchess Gambit Steamboat continues to run, operated by Nadine who is keeping up a trade route with the non-hostile tribals and such there, and no contact with The Pitt is present at all. 

(I'll also switch my vote to East Coast to try to help get things decided, since it seems to be the majority anyways now.)