To go back to the Power Armour for a second - it's always been THE iconic image of the Fallout series, but this time, there's maybe a little too much focus on it in the reveal to ignore. Again - it might not be The Brotherhood Of Steel. Any nut with a gun can get their hands on some Power Armour. But the use of military vehicles, and the sheer volume of it in the trailer definitely points to them. The Brotherhood were already a year old by the time The Great War started, so it would make sense that there are individuals with power armour dotted about the pre-war segments, if the armor at the end of the trailer has been sat there since the bombs fell, then it's safe to say that Boston may have been an area with a lot of support for The Brotherhood Of Steel, possibly even a citadel of sorts. Artwork associated with the trailer includes the line 'Welcome Home', so if the armour has been sat there all this time - and if this really is the player character's home - could the player character hail from a Brotherhood family? Could we be members of The Brotherhood from the get-go? It'd certainly shake things up.