I think it's fine for other turrets. The issue I had was that ship cons could come right up to the base of the cliffs, not being attacked by the turrets on the clifftop, and then power-build turrets on the top of the cliffs. Was very frustrating that there seems little option to defend against mass construction boats in that situation with static defence.
Also from a 'realism' POV, the launcher doesn't need to 'look/aim' downwards, gravity will take care of getting the depthcharge/torpedo into the water :)