Responsive website redesigns are more than just looks, you must factor in your conversions. Customers didn't come to your site to admire it, they came to purchase products, services or to contact you. With that in mind, clients will more than likely choose a company that cares about how their online presence looks, than one that doesn't.
Design & Conversions
Successful websites have a good understanding of design and conversion potential. Every single aspect of a website should drive a customer to their desired destination and attempt at converting them. Navigation, content, images, etc. are just some of the many elements that contribute to a successful conversion.
Cleanliness
White space and high resolution images are nothing to look past. The effectiveness of white space and high resolution images are astounding. Improper margins & pixelated images can make a modern site look dated VERY quickly. Clients often want to fill every nook and cranny with content or images, but the end user does not consume website content like that very well. The site will look too busy, outdated and less appealing for a conversion.
Sometimes Less Is More
Adding numerous elements or content is key to getting the information your client needs to them, BUT don't overdo it! There is a reason that modern navigation implements flow-outs, mega menus, etc. Since you typically have mere seconds to catch someone's attention for them to contact you or make a purchase, make those seconds count! Less is more is an important motto since the fewer options that someone has, the quicker they make a decision.