That's an interesting point. abstracting out parsing/serialization from the data piped between commands would lead to more consistent argument handling for all commands.
somebody wrote docopt (started as python lib) as a generic POSIX usage string parsing (part of the standard). Maybe it could lead to simpler argument parsing and 'user interface' generation, whether static documentation or shell completion scripts.
Also structured output may lead to more relation tools, less regexful ad-hoc parsing, maybe some kind of typecheck so callers can be notified when they need to be rewritten.
