Models shouldn't be hidden by default, as many models have objects that are obviously not hidden but do not have FLGS chunks + objects with children can be hidden, only older versions of Blender automatically hide children when parent is hidden

addons/io_scene_swbf_msh/msh_model.py

@@ -73,7 +73,7 @@ class Model:
     name: str = "Model"
     parent: str = ""
     model_type: ModelType = ModelType.NULL
-    hidden: bool = True
+    hidden: bool = False
 
     transform: ModelTransform = field(default_factory=ModelTransform)
 

addons/io_scene_swbf_msh/msh_scene_to_blend.py

@@ -195,6 +195,5 @@ def extract_scene(filepath: str, scene: Scene):
     for model in scene.models:
         if model.name in model_map:
             obj = model_map[model.name]
-            if get_is_model_hidden(obj) and len(obj.children) == 0:
-                obj.hide_set(True)
+            obj.hide_set(model.hidden or get_is_model_hidden(obj))