I'd support idealized thought experiments even if the world were boring. The answers to boring moral problems come or should come from some process you can decompose into several simple modular parts, and these parts can be individually refined on idealized examples in a way that's cleaner and safer than refining the whole of them together on realistic examples. Not letting answers to thought experiments leak into superficially similar real situations takes a kind of discipline, but it's worth it for people to build this discipline.