Yeah loading the parent is a good idea, it's just surprising nobody thought about it earlier, it's already done for history.dat which has almost the same format so it's strange it wasn't done for command.dat. There are a few examples where it can be useful like 1944d for 1944, and it's only 2 lines to do that, so it's done.
In ClrMamePro you can still create Raine .dat file by clicking "Create" in the Profiler window, pointing to Raine.exe and specifying "RAINE" as emulator type. That's how I maintain my set.