It's a feel.
Visitors feel it.
what would be the impact of using a professional designed template like a wordpress theme.
would that impact on traffic and visitors or not?
Well, here are some similar examples: the design of the break up for men sales page has greatly improved.
Impact on sales? None really or close to insignificant - to the most, it could be around 20%. But it is NOT a radical shift.
With the overall look and feel of the site, I can observe the same.
Even though the site's visual impact has deeply changed, I see no change in number of visits.
I do see though an increase in page views of around 25%.
That's an indication