Honestly I just really want to know if it can be done… I have a few applications that could benefit from this but yes there are other methods to do it. I could foresee using it to assign unique identifiers to static and dynamic objects in the world. Add new Systems and global Managers without hacking into the source code, right now GameMode or GameInstance is your best location. I had a few other possible instances but again all can be achieved in other methods, it’s really just a curiosity to see how much control over the UE4 engine one can achieve.
One reason I ask is because Rama has a thread about plugins where he uses a custom engine, I would think it possible to do the same with UWorld as well.