I am appreciative of the comments in response to my post, and the reason I have not yet answered is that Christian's post got me thinking about what I do want, and so I am doing a bit of hard thinking before I try to articulate it. I consider this to be an important question, and will try to address it soon and responsibly. Without trying to overstate it, I am thinking that there are some fundamental precepts of GTD that no longer work for me, and I need to consider, along the lines of the link Brian above suggested, as well as Kourosh Dini's thoughts, including
http://usingomnifocus.com/contexts-vs-tags/. . I'll let you know.