Let me see if I have this right...

To start an application in Windows 8 without a start button:

First I need to know what name the application uses. This isn't as straight forward as it seems. For example, does Microsoft Word go by the name "Word" or does it go by the name "Microsoft Word"? Same thing about Internet Explorer; is it "Internet Explorer", "IE", or just "Explorer"? This ambiguity isn't limited to Microsoft applications; for example, does Firefox go by the name "Firefox" or is it "Mozilla Firefox"? Note that I would not need to know this if I were presented with the "All Programs" list; I would simply choose the application that I want from the list. In fact, I don't even care what names the apps are going by if I see them in the "All Programs" list since I know their icons.

Okay, let's say I figure out the name that my app is using. All I have to do is type it into the search box that comes up when I press the Windows key, right? Again, not as easy as it sounds since (at least) anyone using their left hand to hold the mouse will have to release the mouse, find the keyboard, and then find the Windows key. This is perhaps easier for righties who can leave their left hand poised over the keyboard, but is an annoyance for lefties.

Let's say that I've managed to depress the Windows key on the keyboard. The search box is finally presented and I type in the name that my desired app is using. This could be any number of keystrokes, but is typically at least three or four. This is pretty easy to do if you know how to type, but is an annoyance for a "hunt-and-******". Once I've finished up with the typing, up pops a list of programs from which I click on the desired one to launch the app. Again, remember our lefties can't click without re-grabbing the mouse since they had to let it go in order to use the Windows key on the keyboard.

In Windows 8 with a Start button:

I click on the start button, hover over "All Programs", scroll to the desired app, and click it. (This sequence may be even shorter if I don't have to scroll to find the desired app.) All of this is done without taking my focus off the screen or my hand off the mouse.

Total keystrokes without a start button: 4 or 5 on the keyboard plus a mouse click.
Total keystrokes with a start button: 2 mouse clicks if I don't have to scroll the programs list; 3 otherwise.

It's astonishing that Microsoft would remove such a boon to efficiency as the Start button. I use "Classic Start Menu" to regain what Microsoft hath taken away.