Downloaded the map and took a look around, here are my thoughts/opinions.
First, a disclaimer. While I find it very impressive that you made this entire map by hand, if it is implemented on the servers very few people will take that into account when deciding if they like the map or not. How the map was built or who built it is ultimately irrelevant to the MCSG player base as they tear around the map looking for the tier 2 chests. Same goes for "side projects", "solo projects", or anything else in that vein - when it comes down to it the players just don't care about that sort of thing
. So I will judge it as is, comparing to maps currently accepted to MCSG.
With that out of the way, onto the map itself!
The theme is very cohesive and the map is well presented. It has a nice polished look to it from the air, and you've established a strong theme throughout. There were no "wtf is this doing here" moments.
Chests are placed in clever spots, and there are little tricks with vines and hidden parkours so you've definitely put a lot of thought into it.
I am not a fan of the caves. Since the hills themselves are shells, it is a bit jarring to walk into a hole in the hill and see that the entire hill is hollow. When using the default texture pack, this also means that you can see the grass peaking though the corners from the inside, and it makes the map feel paper thin.
There are several places where people can escape the map still. Keep in mind that you have to aggressively design against the players, who will scour the map for weak points and exploit them if possible. That's just the nature of the game. If there is one point that allows players to escape the map, you can bet that in a week or so half the players will make a beeline for it every game.
This brings me to one of my bigger concerns. Even if someone places the glass sphere for you (download single player commands, stand in the center, type //hsphere glass 200), since the map is not a circle you will still have lots and lots of places where players can escape to underneath the map. If you continue to do this by hand I anticipate the map requiring many many more hours sealing off the escape routes.
You clearly have the patience and dedication as evidenced by the map. I strongly recommend that you look into installing Single Player Commands, which will give you access to WorldEdit commands in Single Player. There is a learning curve, but it will save you a lot of time in the long run. Also, this will give you access to blocks you cannot access without mods (such as tree:13 etc) that would improve the look of your custom trees
.
In summary, the map is very impressive and looks like a blast, but I fear that you are handicapping yourself by not using all of the tools available to you. If building the map by hand is a matter of personal preference, prepare to spend many hours sealing of the map and patching holes so that players cannot enderpearl out. The only changes I'd recommend aside from fixing the holes and making the glass dome are making the hillside cave walls a few blocks thick.
Best of luck with the map!