Why is conversion testing important? Well, get 12 experts in a room and you'll not find a great deal of agreement on what is right and wrong with a web page.
I will add that, had we all been given access to analytics, we would have come to some more common conclusions. Measure and test.
I've always wondered why copywriters don't get involved in the visual presentation of their stories. I've not met one yet. Designing around Lorem ipsum copy, or writing copy without understanding the visual limitations of a page is crazy. So, yes. Please hire copywriters and start a new generation of writers that get the visual component of their craft.
I will add that, had we all been given access to analytics, we would have come to some more common conclusions. Measure and test.