Add validation to protocols. Upcase protocols.
Validate the mediaType property.
Validate the schemas property.
The root property is baseUriParameters not uriParameters.

That section of the spec is incorrect. See http://forums.raml.org/t/baseuriparameters-vs-root-uriparameters/315/4.
Parse baseUriParameters as Parameter::UriParameter and add validations for it.