Rogers Cadenhead: I used to feel differently, but now that I've worked with it extensively, OPML's an underspecified, one-size-fits-all kludge that doesn't serve a purpose beyond the exchange of simple data. There's little need for an XML dialect to represent outlines.
Randy: On a regular basis, I export my subscriptions from Google Reader and import them into Bloglines, GreatNews and whatever other RSS reader I'm testing that week. A need fulfilled. No?
But for anything beyond that, you're layering an extra abstraction on top of XML that doesn't give you anything good in exchange for interop and escaped markup hassles.
I stopped following OPML 2.0 development when I read that it would be declared "frozen." One battle of that kind is more than enough for me. So I don't know if some of this stuff is being addressed, and I'm not going to find out.
However, if I were building stuff around OPML, I'd be hitting that spec revision effort pretty hard to get some of the issues resolved before it becomes a huge fight to touch as much as a comma in the spec.