I really don't get how can a feature which automatically saves every version of your work, therefore releasing you from having to "save" or "save as", be considered to slow someone down.
Take me for example.
Whenever I turn in an assignment, I always take the .txt template the professor gave, and then put my stuff where it needs to go. So then when I am done, I have an edited version of the original template that I just go and click "Save as" and make that my turn in file. That way I don't save over the original template and I would always do that in TextEdit.
Now, instead of just starting right away, I have to go up to the menu, find duplicate, and click that. Then it keeps the old one open, so I go and close that next. Then I can finally start typing. Then when I am done, I save it and choose the directory for it to go in. This takes more time than just typing and using the keyboard shortcut for save as. Also, there is no keyboard shortcut for duplicate, kinda dumb if you ask me. Sure, you can go make one in System preferences, but then wouldn't you have to make the shortcut for every application that supports autosave?
To me, Lion is a step backwards. Also, it is an OS geared towards laptops, not desktops. I am a huge believe in keyboard shortcuts because they make things so much faster. Having to use the mouse can seriously slow people down. The first second can sometimes be used just to find where your cursor is. Then you move the mouse, and the closer you get to the target, the slower you go because you don't want to miss the button. Then you click. But if you miss the button, you gotta go back searching for it again and click again. Sure, it may not be like a big deal to some, but if you are a more advanced user who knows all the keyboard shortcuts and use them all the time, you will notice how it slows you down.
EDIT: You can go into system preferences and create the "Duplicate" shortcut for All applications. But the fact that you have to go in and add a keyboard shortcut, well that just shouldn't happen. Not to mention now I just hope that doesn't interfere with other keyboard shortcuts in other applications.