Being from Bean Town myself and now living in Hawaii I would be tickled to see either appear in the series. However, in the interest of advancing the universe's story, my Vote would be Switzerland... consider the following:
1. Swiss banks contained a gigantic amount of money. A resource war like the one between the States and China would be highly profitable to weapons dealers and those who FUNDED the weapons dealers.
2. The entire country was prepared against WWIII... bridges set with sapping charges, massive vaults built to house their military and civilian populations. Their neutrality would also guarantee that the Nukes only destroyed everything above ground.
3. A country that has that much money made from weapons trade and war would make sure that they had the best technology at their disposal... and stored in their Vaults.
4. Did I mention how much money they had ...
5. Being in Switzerland the story could tap into so many other rich references. Heck, if the threat of Communism was bad what about the rise of a Fourth Reich? ...Could be an allusion to the "4" in Fallout 4. Makes me wonder what was actually stored in those Swiss Banks right after WWII.
6. The tech could be that much cooler... compare a Chevy to a BMW or Mercedes... who do you want making your powerarmor?
7. Fighting Nazi's... need I say more? Ok... I'll say more... Imagine F.E.V. in the hands of the Nazi's?
Mothership Zeta opens the door to the reality that humans aren't the smartest animal around. And where-as the Enclave developed power armor that is top notch, the inability to make more of it en-mass will spell doom to humanity in the face of a full on Alien invasion. Given the manufacturing skill and scale of the Swiss and Germans, the BOS and elements of the Enclave might send operatives there to secure the resources to manufacture these weapons and gain the upper hand in World Supremacy.
One last note: Where-ever the designers in their God-like form decide to set the story I really hope they include a chainsaw...it's a style thing.