On whether the battle was lost as soon as Guderian was over the river, they were losing it certainly but I don't think it was lost. The counterattacks that failed need not have. If you include those the claim is basically right.
One might still notice that the Russians were penetrated at least as badly and lost even more heavily, but mobilized additional forces fast enough to absorb losses of a similar scale. France did not have Russia's strategic depth and that works against a similar success. But the French did not try nearly as hard, either. Then there is the point that de Gaulle was willing and able to continue the war without metropolitan France. The British could have used the French fleet. French political direction of the war was limp, any way you slice it.
http://www.amazon.com/gp/product/0375414339/102-7673976-2410505?v=glance&n=283155.
Since the second world war and again the Korean war there has/was a move towards training individual soldiers to kill, in fact there have been a number of papers and documentaries on this subject, including this very good book.
On Killing: The Psychological Cost of Learning to Kill in War and Society" by Lt. Col. Dave Grossman.
I will be happy to debate this with you.
http://www.amazon.com/gp/product/0375414339/102-7673976-2410505?v=glance&n=283155..
I am always happy to debate it.