Fundamentally you go against the grain by generating an IDL from source code. I've never seen this done properly such that it is an improvement over just author

Fundamentally you go against the grain by generating an IDL from source code. I've never seen this done properly such that it is an improvement over just authoring the IDL in the first place and generating from that. If your IDL isn't a first-class citizen then what do you expect the derivatives to be?