Wow! You've really put a lot of work into your world. Looks great! Love the pixel art.
I tried to create a new world in 1.7.10, but it crashed . . . I'll do the same if I can figure out the problem.
EDIT: Fixed the problem. Render distance was set to 32, which isn't supported before 1.8.
Render distance in 1.7.10 is 16 chunks, the maximum then. I should have turned my 1.9.2 screen shots down to 16 as well, but . . .
Three shots from a newly-created 1.7.10 world with my seed and three shots from a copy of my vanilla, hard-difficulty survival single player world, Midgard, created July 2, 2014. I copied the world to enter creative mode, then deleted the copy. Screenshots are from today, taken for this thread.
Screenshots are 1920x1080.