I wish they'd focus on implementing basic HTTP support.
* you can't serve non-UTF8 content
* HEAD is totally broken (you can't set Content-Length)
* custom authorizers are useless with 3rd-party clients since you can't set WWW-Authenticate
* 100 Continue is blindly sent before checking auth
And then if they could get around to writing an actual reference document rather than the rambling stream-of-consciousness narratives they have currently, then maybe I'll be able to learn what the heck an "Integration Request" is and what syntax custom authorizers are supposed to return.