My question isn't if these things should be done in a game, it's if they should be added to a game engine that's already bloated.
Truth is the user can already do these things as is.
Layers, just like groups, families, etc are a way to manage objects, albeit ways that do different things, rotation for example, isn't done with families, but it could be.
With that in mind, using a layer to move a group of objects around, at least to me, seems like it should set off some warning flags.
One of them saying "could this not be done another way?".
A behavior perhaps?
Also, I think there needs to be some discussion as to what parts of this are actually related to the camera, rather than the objects positions.