First off - don't think that it's impossible to improve on the verbal. I know plenty of people, including myself, who screwed up the first time, changed their study habits, and did significantly better.
ie. my round #1 (Aug 2001): 7,10,10,S
round #2 (Aug 2002): 10,9,10,R
(For me, this is just great, b/c as a canadian, all i need to do is meet the cuttoffs for my canadian schools.)
But look - just b/c MCAT retesters don't do so well, there is lots to do to improve in verbal. For example, all i did all summer (while i wasn't in the lab), was read read read read read - every damn moment i had. And read challenging, BORING material, and read actively. Therefore, on the actual MCAT, when you get a passage on monks living on the side of a cliff in europe, you'll be able to read it without falling asleep at the wheel.
IT IS VERY POSSIBLE TO IMPROVE! - don't think you can only go down or stay the same!