Based on what I have seen, the content is most important.

We have two identical sites (exact same with the exception of the design). One had a complete face list while the other has not changed for more or less four-years, yet the figures between the two have not really changed. Therefore, that means the untouched one is more profitable simply because the other used up time/money for the redesign.

I do believe in offering new tours, however that is not what you were/are asking.