It'd be too much work to change a 10 - page cover story at a really late stage in the game. (relevantmagazine.com)
Early stages in the game require you to battle monsters solo in order to level up but to truly progress your character really needs to a part of a full team. (thegamer.com)
It might also be that it was considered too dull or empty as it has fewer obstacles or enemies compared to the level length, relative to the other stages in the game. (hardcoregaming101.net)