Added it in our dev branch, should make it out in 4.19 assuming we don’t find any catastrophic knock-on bugs from it. If you need/want it sooner, my change basically changed the UClass markup to be
UCLASS(config = Engine, hidecategories = Object, editinlinenew, BlueprintType)
class ENGINE_API USoundClass : public UObject
Then went and added BlueprintReadOnly to all sound class properties, and removed ENGINE_API from individual functions. ENGINE_API was needed due to a linker error in a separate module using sound classes that occurred due to new generated code by UBT. I also went and did the same thing to the UStructs in that file for settings so you can inspect sound class properties, etc.