Are there any necessary features that you've found missing in msgspec?
One of the design goals for msgspec (besides much higher performance) was simpler usage. Fewer concepts to wrap your head around, fewer config options to learn about. I personally find pydantic's kitchen sink approach means sometimes I have a hard time understanding what a model will do with a given json structure. IMO the serialization/validation part of your code shouldn't be the most complicated part.
The biggest issue missing from most conversion and validation libraries is creating models from JSON Schema. JS is ideal for central, platform agnostic single source of truth for data structures.
One of the design goals for msgspec (besides much higher performance) was simpler usage. Fewer concepts to wrap your head around, fewer config options to learn about. I personally find pydantic's kitchen sink approach means sometimes I have a hard time understanding what a model will do with a given json structure. IMO the serialization/validation part of your code shouldn't be the most complicated part.