Now as we live in era of ships, would it be completely stupid idea to make it
possible to travel around world? What i mean is when you go far enough east,
you get to west and so on, you got the point.

As I understand it, the outerworld of bat as it stands now isn't the entire
world, but simply a super continent (well, and a couple of other nearby
continents/islands). There is the continent that the Zhentorians come from for
a start, possibly somewhere the vikings come from (unless they have an area?),
stuff like that. So really going off the east side and appearing on the west
side (or whatever) doesn't really make sense.

I could ofcourse be completely wrong though But that's just how I've always
thought it was