In Survival Games 1, I wish you added more islands. This way, there would be fewer water fights, which can take up to a couple of minutes. I also think you should add a tiny town and some more of those 2x2 trees.
Survival Games 2 doesn't need to much more. Maybe some puzzles, mazes, combo pads and stuff like that in the underground? And an enchantment table.
I've never liked Survival Games 3. I think it's a bit too big, and it is not enough landmarks. The structures look nice, but it is not worth climbing up the mountain around corn, and it is not worth climbing up the giant tree.
Add more underground traps (lava, anvils and cobweb traps), another temple with a lots of mazes, keypads etc, and some huts on top of the big trees. The huts should have small bridges between them. You should also add some teleporters (by using command blocks) at the corners and on top of the mountain.
Survival Games 4 is pretty good as it is. A BIG crane would be cool, nearby the spawn. And a minefield.
Other stuff:
- Add villages to 2 and 4. Use MCEdit to give them special trade items. (for example: an iron sword for a wooden sword with fire aspect I and a bow + 1 diamond for a bow with punch II) Make sure this is not too overpowered and make sure to hide the NPC's good.
- Add command blocks to all of the maps. I am sure Team Vareide will be able to make some awesome traps by doing this. (for example: you step on a pressure plate and get teleported 50 blocks above the map.)
- Add traps with anvils and tripwires.
- Add a beacon. In MCSG, you usually have a spare golden ingot. You could use it to get special effects.
Hope you add some of these, and sorry for the bad grammar. I wrote this while playing.