I have no problem whatsoever with British accents. I wouldn't mind English accents from all over the world, but I'm not a huge fan of mapping real-life countries on fantasy ones. I didn't like how in Dragon Age there was a France rip-off with heavy French accents and Italy rip-off with heavy Italian accents. I know Forgotten Realms are largely based on the real world, but it doesn't need to be further reaffirmed with accents. Besides, there is a lot of diversity just among British accents (as already seen in the game). There isn't one British accent, not to mention other European English accents.
I wonder if people would be as bothered if all the characters spoke like Americans.