If I could offer my input on this subject, as I think this discussion highlights a pivotal piece of advice that newcomers can easily misinterpret as GTD gospel. I think the problems stem from people having such varied interpretations of the GTD models which are themselves just recommend best practices from a 20th century thinker. I also think David Allen’s comments and guidelines (including his personal statements, books, company, trainers, and associates & affiliates) are given far too much weight in how to be productive or actually accomplish goals and complete tasks (saying “getting things done” is such a misnomer in this context) in the minds of many. We need to evaluate everything with skepticism and critical analysis before we accept it as a good idea, let alone gospel-like truth.
The perspective that I often fail to see people consider is that in order to actually accomplish goals and complete tasks you should do whatever works for you; a variety of tools and tactics exist to make doing whatever works for you, be effective and efficient. I think anyone who makes blanket statements about never using a tool should be considered very lightly and with a huge grain of salt, without being cliche. Every tool has its appropriate usage and its corresponding antithesis of abuse. (Please note, I think many of David Allen’s (and DavidCo’s) statements are incorrectly interpreted. I believe this is the case as well because it’s often noted that the GTD setup guides on his site, whose target demographic is new comers to GTD, are just recommended guidelines to make initiating GTD easier).
Think of it in terms of a toolbox: you have a hammer, screwdriver, saw, and tape measure let’s say. Each tool has a valid and best-use-case scenario; we don’t throw the baby out with the bathwater when something doesn’t immediately work, we tweak it. Contrastingly, we need to consider that if the only tool in someone’s toolbox is a hammer then everything starts looking like a nail; this is obviously an incorrect approach as well.
I think OmniFocus’ solution is quite elegant and correct via offering both types (parallel and sequential projects) because many people have different approaches to personal project management. Some like large amounts of granular detail such like a full project management work breakdown structure while others prefer a more loosely interpretable adaption of an outline of general steps.
I, personally, use sequential projects a lot, but make it so that the “blocked” actions always show up as “blocked” in my perspectives so that I know they’re not immediate but could be available given a change in context (see many of the noted examples above using Fiona, these are good examples). The ones that are more bolded / brighter are the clear next action for that project and I always know where my attention should be directed but I can choose to ignore the order if it is appropriate. As I noted above, there are many ways to “skin the [proverbial] cat” and the best way is the way that is most efficient and effective per user.
On a side note, you could create an implementation of GTD ignoring project types via utilizing just tags and due/defer dates to determine if an action is the “Next Action” or “blocked”. I don’t recommend it for everyone (or ever a newer GTD aficionado), but when I mentioned the actually usable OmniFocus 3 to one of my like-minded friends, who rather disliked OF2’s lack of flexibility shall we say, immediately theorized and planned on implementing such a strategy into OF3 on his Mac.
