I truly haven’t mentioned physics constraints in the original question, as they seemed so important to me, that I’ve considered them an obvious requirement, plus you can’t imagine KSP without them, which is also why I’ve used it as an example.
However, I don’t agree that setting them ‘will always be a nightmare’, as adding them between Static Mesh Components proved very easy, and the only time they were a nightmare was when I had child actors. This forces you to add them during begin play, as child actors are fully initialized only then - and that’s the core reason they were so difficult to work with and debug.
And it seems like with your approach, even though child actors are still not used, there is a similar approach with physics constraints - you can’t set physics constrains between actors - only between their static meshes (am I wrong here?). This again forces you to do so at runtime, which is a lot harder to debug.