And should we edit Bob Marley?
Oh, these are always so much fun.
Up and down can be extraneous or useful. For example, some people claim Bob sat down is redundant.
Well, that depends on what we already know. If we know Bob is standing, sure, it's redundant (though not exactly criminal). But if we're early in a scene, and haven't positioned Bob in the readers mind, there's a big difference between Bob sat down (because he is standing) and Bob sat up (because he is lying down).
To go back to an example form the original post, I prefer He sank back into the leather seat rather than the improvement He sank into the leather seat. Sinking back into something is different from merely sinking into something, as the latter gives the notion He may be headed for the floor, and possibly disappearing altogether: He sank into the leather seat and was never seen again.
There are also times when rhythm and common usage may make the addition of these extra words a good idea. My ear prefers She waddled over to the jukebox to She waddled to the jukebox. (This is partly because the syntactical slot filled by over is begging for something--She waddled across the scuffed linoleum toward the jukebox or some such.)
And there are phrases like He wandered over to assess the damage which make no sense without the 'excess' word; He wandered to assess the damage makes no sense.
The name of the game as I see it isn't cutting words; it's cutting words when that involves an improvement. For example, I wouldn't have counseled Bob Marley to change Stand up for your rights to Stand for your rights. Up, down, over, etc. should always be carefully examined, but that doesn't mean the writing is always improved by their removal.
As George Orwell put it, there are certain rules for writing, and one ought to break any of them rather than say something barbaric.
