Hi simonm,
Love your site.
I agree 100% with what your saying.
It is more important to sell the product not the site. I see 1,000's of sites that will never sell one thing for the customers. I would say the problem lies in both the customer and the designer. The customer should do the necessary research to find out what will work on line and the designer should help the customer in finding the right approach.
A lot of web designers want everyone to see what they can do can could care less if it will work for the customers. You have a splash page then a couple of really neat looking little tricks and ten pages later your at the product.
I can understand the customer not having the time to do the design work or
seo for a site but they should still know how to read the stats, know what it takes to get ranked good and know what is in a good design.
If I'm running a business I may not have time to do it all myself but if I'm going to put it online I should understand how it all works.