Rationale for components

The taskbar was the number one thing I vacillated on how to deal with it.
It solves a real problem. It gives you constant access to desktop-type functions.

That said, it clutters up the look. And it's not really needed 90% of the time.
Hiding it isn't necessarily the answer either. 
First because when it shows up it either has to resize the window or it overlaps the program, and for various programs, either one or the other is annoying.

Win 8 had a point about changing to a screen that offers deeper functions.
What it got deeply wrong was that there was zero attention to ergonomics. 
But the idea—might be salvageable.

What if we make an overlay—I call it a "control surface", that supersedes the functions of the taskbar and allows all the conventional actions we associate with it, and the start menu?
How do we got to it? Well, part of designing a robust solution for something like this is there should be multiple ways—this will be a theme. 
Way 1—the slow way, but the way users are likely to find just by exploring— is to click the taskbar at the bottom. (this is on by default but can be removed entirely by power users who want a clean look); 
Way 2—hit the windows key; 
Way 3—for people like Ross and me who have the windows key disabled— we steal the alt + tab function. That's kosher as long as we still make it easy to switch between programs. Which we will!

My vision for the control surface is to make it highly configurable.
 We can take full advantage of mouse and keyboard in it without interfering with background programs because it will act as a kind of program in its own right 
(though its visual appearance makes it clear it's part of the system itself, hopefully).
"Full advantage" is relative, though. I constrained my design choices to mouse, and the common gaming keys. 
That is—Q, W, E, R, A, S, D, F, Tab, Shift, Control, and Space. C, ~, X, and Z, and V can be used, 
in roughly that order of priority based on distance from WASD if hands are held in the gaming position 
(Key remapping for exotic key layouts should be available but not necessarily a priority for a minimal viable product).

However, everything needs a starting point. What you see here is one idea for the default layout.
Active programs are located in the center of the screen because that's the ergonomically favored position— 
on average your cursor was likely to be closer to the center of the screen than the side if you activated the control surface while using a program.

By default the active program can be chosen by moving the mouse over the program and clicking, or pressing tab,
 or keeping alt held/win held and spinning the mouse wheel until the desired thing is selected, then releasing. 
If you press off of it, you can re-select it by pressing alt. 

Programs with multiple instances like web browsers can be configured do show them either as "blips" (shown with Brave) or "nodes" (shown with Word). 
For things where a name is needed to differentiate documents, nodes are ideal—lines connect back from a list in an easily interpreted clockwise order.
 The selected item in the list is highlighted to make selecting it simple. 
In the example of Brave, you can see that many nodes—Amazon, Googlemaps, Accursedfarms—could be IDed by their mini-icon alone. 
But because things like YT might have multiple instances, the name of the page would also appear below the cluster when it's selected.
 Notice also that the nodes in Word have collapsed, as they're not currently in use.


On the left we see the speed dial. This can be selected by tapping control.
A program or commonly used directory can then be launched simply by dialing the hot-button.
By default it stores a maximum of 12 (see the alphabet keys above).
For power users needing more options, tapping ctrl allows you to flip between "pages" of hotkeys.
An option to "nest" hot-buttons—dial something by pressing a sequence of keys—would allow up to 1,728 (12^3) hot-button options just by dialing 3 keys, but would be much more oriented towards power users.
All this is possible because, remember, this is over-riding all back-ground hotkeys right now. Programs could also be selected by using the scroll wheel to sift through and clicking on the desired icon.

On the right we see the program/file directory.
This can be selected by tapping shift. Tapping shift again changes it to sort between programs and files. 
If you tap and release tab, it changes how programs or files are sorted.
By default programs can be sorted by name, installation date, size, and ideally could be tagged by the computer owner to give them more tags (EG, #productivity, #game, etc).
If you tap and hold until the tab-key button fills up (think video game menus), it opens the filter menu for more precise searches
(restricting searches to only one drive, specifying a range of installation dates for programs, filtering programs by publisher, etc).
 If you tap "~", you can open a search bar (sorry, Ross, but I think it can be useful). 
The "~" was used to open the console in tons of old-school games so I felt like it fit, as well as being within easy reach of the left hand in a gaming stance.
Navigation of the menu could be with the scroll wheel, or hovering above the top or bottom of the menu with the mouse to select a  program (the midpoint would be neutral and not result in scrolling).
 Pressing space, or left clicking on the program icon, would launch it. The options in the menu are intended to scroll by as in a phone contact list, with opacity increasing towards the center. 
The selected icon increases in size as it flips past the center, somewhat like an icon hovered over on the Macintosh taskbar.

A valid critique would be that in this mock-up I didn't really do much to show how menus might look when de-selected. Likely I would just have them fade and shrink slightly.

I emphasize that what you see here is a conceptual default. This is a system I think I could happily live with. But you could ideally do anything, including make the control surface be blank in configs.
Rather than being switched to, a circular version of these or other menus could be brought up with the specified—or other—hotkeys, as designated by the user.
Interestingly though, the effect on ergonomics would in theory mostly be in eye-travel distance.
Because of the way the menus are laid out, it should be theoretically possible to navigate anywhere in them, or use all their functions (except the search in the directory), with only hotkeys and the mouse scroll wheel. 
The option to roll directly over and click on items would exist mostly for learning the system or simple convenience 
(a design principle I use is, if it seems intuitively that a thing should be doable, and it can be made doable, it should be).

There are some other miscellaneous indicators thrown in. With the exception of F1 for the power options. 
The rest aren't tied to any hotkeys because I think they should be infrequently used, or they're indicators. 
Needless to say indicators could be moved to the main desktop, moved, or RE-moved altogether.