See #5461 for the reverted attempt at that. Basically, cargo metadata prints not enough information about resolved dependencies.

The bits of info missing from cargo metadata are:

• Which dependency applies to which target: currently we can't distinguish between normal and dev deps cargo metadata's resolve output doesn't specify depenency kinds #3984, cargo-metadata's resolve doesn't identify the kind of the dependency #4631
• What are the platform restrictions for a dep? cargo-metadata doesn't track target-specific dependencies #4632
• Which name are you supposed to put in extern carate name? This covers - to _ translation, as well as Cargo.toml level renaming.