Well yes, and then the island was sunk immediately after Garling killed Rocks. I'm not saying Plan A was to sink God Valley before Imu knew it was a hotbed of Davys, I'm saying Imu did it in response to that new information.I don't think that fits too well. God valley was found by pretty much by accident by garling. It was framed as a remote location outside of the world government where bucaneers laid low. Imu only showed up as xebec revealed himself in god valley.