They will never change the engine, they put decades of work into this one and no other engine can compete when it comes to this type of sandbox moddable games. The best we can hope is they are making meaningful upgrades to it but even from the trailers you can immediately recognize bethesda combat and animations when NPCs start moving.

I am in a Skyrim DLL modding discord that has pored over any footage of development tools. They have noticed that BGS are using a version of the Creation Kit for developing the game, so I think it’s basically guaranteed that it’s a version of the Creation Engine.