IMAP URL scheme <draft-newman-url-imap-05.txt>

I'd like to review "draft-newman-url-imap-05.txt" against
"draft-masinter-url-process-00.txt", as much to ask
"are the criteria adequate or too restrictive" as "do imap URLs fit?".

2.1: syntactic compatibility
The only other URL schemes that access "message in repository" are
"news" and "nntp". I suppose IMAP doesn't have any way to reference a
message by its message ID, although NNTP does by its message number
within a news group.

The section 8 exception for "relative IMAP URLs" is just unacceptable.
I'm skeptical that "IMAP4 permits the use of any hierarchy delimiter
in mailbox names" is a good idea. We avoided this in "file:" and think
the same arguments apply here.

2.2: is the definition really complete? I guess I don't know enough
about IMAP to know whether you can read this spec and write the
program that translates IMAP urls to IMAP calls. Doing this for most
protocols is really hard.

"2.2.4 Definition of URL schemes not associated with data resources"

Do IMAP URLs reference data objects always? Even the search mailboxes?
What's the definition of the interaction? 

"2.3.1 Proxy into HTTP/HTML"

Do you have an HTTP<->IMAP gateway?

Nit:
Now that draft-bradner-key-words is on the way to RFCdom, I'd like to
see new RFCs reference it for the definitions of MUST, SHOULD, rather
than repeat them.