That would be broken by necessity rather than in implementation. There simply is no way to represent a numerical sort without putting a callback in the source, but the compiled form of that sort doesn't use any callback. The choice is to represent either the original or the compiled form more closely. I prefer the current behaviour of emphasizing the compiled form since that's what the module is for, after all. Maybe that should be, if implementable, a user selectable option.
Good catch about the reason of the - vs <=> slowdown. I didn't make that (so very obvious, in retrospect) connection.
Makeshifts last the longest.