Just a thought.
When there is a possibility to create shaped meshes / entities, then there would be possibility to manipulate their surface too
f.i ent_flip_mesh ; ent_color etc.
flip_mesh has some advantages. For example entities react to fog etc. So when creating an sphere mesh and flipping it, there is a way to fill room with visible fog without making a huge map entity cube. useful for open air games, flying or smth, that needs this atmospheric look, probably better to make visible skybox too that is blended with the fog... although when no image is possible then with ent_color you could color the entity.

Cheers!