Well, I'm pretty sure that I'm someone with the condition who has tried it, but perhaps you demand a formal diagnosis.
Re the follow through, I suspect that there is no organization system that doesn't demand follow through. Now, it might seem intuitive that someone who has trouble with follow through would do better with a simpler system, but simple isn't interesting, and interesting is essential. GTD is interesting to me, and supports a fair bit of puttering--puttering that may feel like a waste of time, but, again, it's interesting and helps to maintain engagement with the system. Deciding that THAT context should really be split into THOSE two contexts, and those should be combined, and y'know, the whole context list could use revamping and maybe the project list could use reorganizing, too.... Hyperfocusing on one's task management system may not be a productive use of time, but it's better than ignoring it.
I do find myself wondering if the GTD model works better for the way that programmers form mental models, though. I remember reading, though I can't find the source, that there are two major ways that people form mental models. For lack of names, I'll just call them A and B. Type B people are the minority in the general population, but the vast majority of computer programmers are type B. I strongly suspect that the GTD model, with projects and contexts as two different ways to "cut" data, may work for programmer types. I suspect that plenty of programmers are ADHD--hyperfocus is useful, one might even say essential, for programming--but I wonder if people who are both ADHD and type A might find GTD unusable.
I do find that the two-minute rule is doom; I absolutely cannot use it. Shifting away from processing my lists means that I will likely not shift back.
And I need to maintain a ruthlessly pared-down list of active projects. A million projects in Someday/Maybe or support material or Thoughts lists is just fine, but the active projects and actions must be as minimalist as possible. I have a very low tolerance for long lists.
On the other hand, the "cranking widgets" model, writing a very small completely understandable action, doing it, and checking it off, is oddly rewarding. GTD just has you create a sort of "bookmark" Next Action when you stop working on a project, but when I'm having trouble focusing I will often keep writing, working, and checking off actions, even though there's no functional value in doing so.