Blacraft Forum

Yqt, could you tell me where you want Mystic Marsh moved then?

"There is a limit of three strongholds per world. All strongholds are located at random positions in a radius between 640 and 1152 blocks from the world's original spawn point, at 0/0 (but may extend further in or out of that area). The three strongholds are spawned at roughly equal angles from the center point of the world (that is, each stronghold is in the region of 120 degrees from the others, measured from the origin). The game will not generate a stronghold partially above-ground: any portion above the ground layer will be replaced with air blocks, leaving a cutaway."
http://minecraft.gamepedia.com/Stronghold

Blotz, chunky borders aren't the reason why we change the seed, they just mean that there is simply no reason to keep the old one and I can't verify that people actually deleted the old seed so don't ask me if everyone did it.