It sounds ingenious, but dangerous. For example, what happens if you make a mistake and then immediately switch to a different window while the keyboard is deleting your mistake and then typing a correction?
As for reaching for the mouse, moving the cursor, clicking in the new window: wouldn't happen faster than the keyboard s autocorrect.
I don't think that works. The keyboard can't buffer your input while it waits for a match on its autocorrect dictionary.
Imagine how that would seem if you're typing slowly? You will expect each keypress to have an instant output on screen. But nothing would appear.