I would propose this approach:

1. Python should implement both IDNA2008 and UTS#46, and keep IDNA2003
2. "idna" should become an alias for "idna2003".
3. The socket module and all other place that use the "idna" encoding should use "uts46" instead.
4. Pre-existing implementations of IDNA 2008 should be used as inspirations at best; Python will need a new implementation from scratch, one that puts all relevant tables into the unicodedata module if they aren't there already. This is in particular where the idna 0.1 library fails. The implementation should refer to the relevant parts of the specification, to be easily reviewable for correctness.

Contributions are welcome.