Were such not adequately employed, many returning visitors may have become frustrated in their attempts to find a corresponding new page that they abandoned the site, never to return.
Have you considered economic factors?
It's on the same caliber as moving a real store across town and placing a 3" post it note on the door of the old place and then wondering where all the customers went.
If I were your client right now I'd be talking to lawyers about ways I can recover my loses through you. Someone with 15 years experience should know better.
Aside: There is no need to take anything personal here. People are responding in what little time they have, and seldom have time to elaborate on the niceties.
Pushed for time is one thing. Niceties - I agree, not necessary. But there are too may people responding on forums in such a way that demonstrates a certain lack of manners. It's just not necessary.
Anyway, I thank you for your assistance. Unfortunately my client is still wedded to his designer for reasons I do not need to go into on here.