If the map is impossible in 1.8.9 (the recommended Parkour version), it absolutely needs to be changed. Also, if you think the build is too big, then try to shrink it a bit; you've got unlimited time, don't feel rushed to submit! Otherwise, I'd say the theme isn't very original, and the build is mostly pixel art (even if 3D, it's still pixel art). The parkour looks fun, but also a bit repetitive.