Why I do things the way I do
I like the idea of using as few programs as possible. I use Evernote for mind-dumping - ubiquitous collection of ideas, project support actions, etc. I can store my someday items (as notes), to read items, etc all in one place that is available everywhere (android/web/computer) and offline. So I started using Evernote for next action collection as well, and putting them into one note separated by context worked pretty well because I can pull up my @Call list driving down the road thru the android app and knock out a few calls.
If I were using one note per task I could do the same thing, the downside is that I couldn't print a "task list" like I do now, also scheduling would be a bit cumbersome (although not in conflict with GTD, I don't think). But it would still take considerable work to modify/add the notes w/subjects to become next actions.
Also, there seem to be a shortage of real ubiquitous to do list tools out there that are accessible anywhere...
Bottom line is that I may just be trying to do too much and no tool will solve the problem.