They tested a lot, Cradle and Stature have working spawns and crate placements but lagged and had glitches like guns falling through the cradle walkways and the statutes lowering frame rate.
Silo is a linear map but they added in all those alternate paths in source to make it work, same with runway so that's what we can do for dam. We'd make the underground system larger, maybe make the island available and larger and connected to the underground system or something. You know make use of the water area being so massive, make a second level of th tunnels that runs below the water and to the island.
Course I'm just speculating here and can understand if you don't like my idea of the tunnels.