Although some members will tell you otherwise, it is possible to expand the map, even if only slightly. While the engine could probably not handle the map being expanded (ie- more grid squares added along the vertical or horizontal), it would be possible to open up, or even terraform, existing areas currently cut of by the green Cursed Wall. Myself and other users such as @TwoJay have spent time wandering around, and even building settlements well on the other side of it.
Here is a good thread which will argue the merits of both sides of the subject. For the ‘not possible’ side, see Multiguns posts. For the ‘possible’ side, see BiJays posts. The final thing to consider is if there is a willingness to actually do so on Funcoms part, and at this stage, there doesnt seem to be. But you just have a read of this thread, and make up your own mind.