Been thinking about your suggestion and re-read your posting and the question that springs to mind is WHY.
It seems to me you start on extremely shaky ground in trying to separate 'folk' and 'tradition'; they are two sides to the same coin - one referring to the origins of our songs etc.; the other to the process that shaped them.
You say "a song's origin is a total irrelevance to any definition."
Then where does the 'folk' bit come in? It refers precicely to the communities that made them (IMO), took them up, reshaped them, claimed them as their own and passed them on (put them through a traditional process) over and over and over again until they manifested themselves in tens, dozens, even hundreds of differing, identifyable existences. The origins of the individual songs may be irrelevant, to the singer, that is, (I believe you have spent a fair slice of your life trying to sort out individual origins), but the origins of the genre as a whole is not only relevant, but crucial, it is what they are and it is what we are and where we've been. The communities that once cherished the songs no longer do so; so we are dealing with something that is no longer in flux but is fairly solidly set (the rigor mortis set in long ago). Doesn't mean we can't go on singing the songs or making new ones in their image, but pretending that the processes are still alive and kicking is little more than putting lipstick on the corpse   
Taking folk out of the equasion is like dividing the siamese twins and giving the single heart to the one you personally prefer.
"but we are in the minority and it's about time we accepted that.)"
Where are we the minority Steve - on Mudcat, around the clubs, among the people who sort out the album shelves at Virgin Record Megastores? I suggest you take a stroll around your own book shelves, or mine, or those of Vaughan Williams Memorial Library, or The Irish Folklore Society, or The School of Scottish Studies, or The Library of Congress, or all the comparable organisations all over the world who have collected, researched, annotated, articuated and indexed (ie established clearly for the world to refer to) the definitions of 'folk' and 'tradition' we have used up to now and continue to use (I take it you own an 8 volume set of 'The Greig Duncan FOLK SONG Collection', or receive your annual FOLK MUSIC Journal......). What do "we few, we happy few, we band of brothers" (sorry CS - and sisters) do to give access to our music to 'the world out there' (to borrow a phrase from those who would have us believe that there is a 54 million strong army with an alternative definition) - announce a U.D.I from our documented and researched material?
We have definitions for the terms we use which gives us an advantage over those who would de-define our music - we have a consensus; something to point to and say "there, have a look at that and see what you think". Compare that fact with Tom Bliss's list of 'definitions' or Sean Sweeney's - could you run a club, or write an article, or give a talk, or issue a CD or explain 'tradition' and 'folk' to somebody interested enough to enquire or ask to participate, using their random gatherings? - buggered if I could.
I've occasionally been accused of inventing my own definitions - often by people who have just made up their own definitions. I've never invented a definition in my life - spent nearly half a century trying to understand and to pass on anything I might have learned about them, but nope - can't think of a single one I can write my name on (wonder if anyone else can).
The irony of all this is that the existing definitions certainly need a revisit and adaptation based on what we have learned, but throwing them out to replace them with something 'convenient' is a little like knocking your house down because the pictures need straightening.
Jim Carroll