i think that the next fallout should not be in boston because its not really that known and seems to be to base unlike the other location the prevouse fallouts have been based ,what people like about the maps is how many monuments or famouse locations there are,like fallout three the washington monuments and the white house ,and in fallout new vages hoover dam and vages itself ,although there are many differnt location is boston i think that LONDON could really work ,because if there is one thing evrone loves in fallout its the ruins of citys . and london would really be good to explore because there is so much storyline potential both main and sideline ,it also posses same qulitys as fallout 3 such as metros and lots and lots of monuments and location such as the london eye, big ben,london bridge, the gherkin,trafalgar square,buckingham palace also the citys basic layout would be perfect for fire fights and it would also open up whole new relms of devolpment for fallout by changeing coutreys ...not permanently but just as an experament .
for exaple mabe a storyline could be the local built a wall cuting of london from hords of mutated creature such as super mutents and other creatures in fallout and mabe the super mutents attempets to break through and you have to go in there and stop it ,but its takes a turn when you discover there is a mass population of people in there so your job is to get them out .....this is just an example of what you could do however you i still think the idea of fallout being set in london would be a very good idea