Wonderful news from Japan today as Koei Tecmo confirms that no, you won't need to import Berserk Musou, because it will be coming to the west. This new Berserk game will be coming to the PS3, PS Vita, and PS4 in Japan on September 21st this year, and will be coming west (both the US and Europe) sometime after that with Koei also mentioning that we will also get it on the PC as well (though likely as a port).
As for what the game is about, something that the E3 trailer told absolutely nothing about. Well, the official website is now up with a trailer that shows actual gameplay.
The story of the game will, of course, include the Golden Age arc, but it will actually go beyond that to as far as the Millennium Falcon arc, the furthest we've seen into the Berserk world outside the manga to date.