Okay, I've made good headway on my CtG map. The basic structure is set up so far, with a large central hill-castle full of traps and twisty passages, as well as a tower for each team. It's mirrored, and the towers are tall enough to discourage flyovers. The central structure has a solid spike reaching straight to the top of the skybox. Everything is made of lihzahrd bricks, though there's a surface carpet of jungle between the bases and the central hill. I plan on adding a bunch of smaller ruined buildings in those spaces. The idea is that I'll box the entire area in with lihzahrd bricks, then give each team a chest full of supplies (stone, wood, rope, bombs, etc.) for a KAG-esque feel; explosives can be used freely without breaking the actual arena, and players can build their own structures while destroying enemy ones.
Of course that would necessitate reloading the map from a backup for each new match, but I think it might be worth it. Once I have a more complete version I'll post a download link for it.
Basically the idea is to have sniping locations both in the bases and in the outside part of the central structure for ranged players/mages with beam weapons, give the fliers/cone of effect fighters a wide open area to dogfight in, while preventing either from completely dominating by forcing everyone to funnel through an area dominated by melee, explosives, wall-piercers, and rebounding shots. I placed the traps to discourage camping as much as possible.
Basically I wanted to have a very short list of banned items: picksaws, tools/blocks that interact with wires, and... that's it.