Fascinating discussion.
I tend to dislike hurt/comfort as a B7 genre, unless it's done rather subtly. I think Neil is correct that one of its 'purposes' is to allow the writer and/or reader emotional closeness to usually distant characters, frequently Avon, though I've seen it done successfully with other characters, including Travis and Servalan, which might tend to support Neil's analysis. I'd agree that in this sense it's essentially a non-overtly sexualised version of slash.
Personally, as a writer, I'd prefer to use other ways of gaining closeness to the character, the easiest being to use their point of view -- if you want to expose Avon's inner child then just walk right into his head and expose it....
Tavia