Looks really good, and detailed! =) I love the caves.
For only 20% done, it shows a lot of potential, and I can picture some unusual types of PvP being held.
Also, I saw some decently flat areas for PvP, but they're quite isolated - Small fights scattered around the maps, and long and treacherous chases. C:
It doesn't look large, and the Cornucopia looks like it'll be fairly easy and straightforward to PvP on.
Also, the Cornucopia has 4 different block types pointing in the 4 cardinal directions - that will make it exceptionally easy to find various routes, much like on Icarus with the 4 different valuable block types (I believe it was diamond, gold, redstone, and emerald?) I personally use the cardinal directions for when I don't have a route, I can definitely see something coming into existence like the "Diamond route" on Icarus, like maybe the "Stone route"
(
http://prntscr.com/44dyft)
Can't wait to see the finished map!