andyjim wrote:

My thing is fresh thoughts. I generate them all the time. I don’t
gather material, I generate it. So my needs flow from this MO. I need to
be able to launch a new item instantly with a keystroke code. So many
times I’ve had a thought, out of the blue and possibly unrelated
to what I’m writing at the moment, but by the time I distract
myself opening a new file or even simply backing out of a lower outline
level to start a new heading, the thought has receded behind the
mechanics of preparing a place to write it. I have shifted my mind out
of hearing the muse and into preparing the ground. It’s a
different, and for me, distracting mode to have to go into every time
you have a new thought.
So, immediate new (and independent) item from keystrokes is one
requirement.
I want an absolute minimum of distraction on the screen. No toolbars, no
main window, the whole screen covered with a neutral, non-white (i.e.
non-glaring) background. So at this point it’s just the blank
screen and my new item, which itself has no toolbar, and minimalist
borders. Not even a title bar at this point (optional, for later). Now,
in a split second, I can write the new thought without distraction.
There must be no requirement to name, class or connect the new item.
Open it, and write.

The above seems to be about the front end of the process, capturing written notes. What OS and hardware do you want to use?

On Windows, I'd suggest WriteMonkey. On iOS, Drafts seems to launch a new app automatically (though I never had the chance to try it, as I don't have iOS 7). On ChromeOS, Writebox could do this. Dropbox could be the place to gather all the plain text files.

Scrivener also has a distraction-free writing mode, though it takes a couple of clicks to get there. On the plus side, it could connect more seamlessly to the next stage of the process below.

Then think about where the item belongs in the
scheme. (I know that’s not a unique concept). Once it’s time
to place the item, I want to be able to class by keyword(s), subject(s),
topic(s), project(s), priority, and any other classes (customizable by
user). I envision doing this in one table, attached to the item.
Classing can be hierarchic but is not required to be. Ideally the system
does not constrain you in any way. (I know CT in particular attempts to
do this)
I want outliner capabilities, implemented in a minimalist way, within an
item, as well as with tree structures for subjects, projects or any
other class you want to look at from a tree perspective.
I realize (though with very little use myself) that CT does many of
these things, and other apps do as well, to greater or lesser degree.
But the minimalist interface is a necessity for me because the way my
peculiar mind works, and my proposed system for ‘classing’
or ‘keying’ items in a single table, after writing the item,
appeals to my seeming need for order and disorder at the same time. Plus
I don't know of any app that does all this.

As you note, CT can do almost all of this. It's not the most minimalist of applications, but you can customise much of the colour scheme, hide buttons, remove panes, and there is a full-screen option (though it could be better). Not sure I understand your thoughts about doing the organising in a single table. In CT, the categorising happens within the text note item, however there is a Summary pane that can list all the properties in a box.

I want some column features, similar to Gingko, for lining up groups of
items to work with. This would also occur within an otherwise empty
screen.

CT's floating windows can be dragged around against a blank desktop to arrange them in a column formation, but they are not fixable into columns.

One more 'justification' to add: I have 20+ years' backlog of thoughts &
items scattered. And I get worse every year, generating this past year
over 300,000 words. I need to corral all this into a cohesive system
that enables me to readily access everything I've written (and in the
same app in which I write, because the shifting around that will be
required if things are spread across various apps, folders, etc is
intolerable). Some day I will write a book(s) from all these thoughts,
so I need to be able to find and manipulate these thousands of items.
This is why I need a multi-key system for classing and connecting
things. I gotta be able to find it by subject, topic, keyword or any
other scheme I may come up with. My proposed system will accommodate all
this (I think). It would also (I think) be highly extensible,
customizable and adaptable to many needs and styles.

Again, this sounds very much like a problem that CT can solve.

These are just some suggestions off the top of my head. I certainly wouldn't want to discourage you from developing your own software. As a happy CT user, I am naturally prone to suggesting it, but I realise that it can take a big effort sometimes to get to grips with it.

On the whole though, it sounds like your needs could be served by some kind of a plain text system for capturing and gathering notes, and then organising them in an intelligent database. Piggydb might be another option (although I find the interface even busier than CT's).