You can modify your logo and brand. Revamp your brand by finding better ways to integrate your brand colours, logo and messaging into your web pages. You can create your website design. Change the old designs; this is an opportunity to catch up. Get rid of that common, out of date stock art and replace it with creative graphics works.
Perhaps your website has become less user-friendly over the years. This often happens over time as businesses continually add content to their website without properly organizing it. This is a great opportunity to streamline your content and features. You can focus the redesigned website around new products and services.
New technology can be federated to make your website more useful to visitors. The addition of interactive maps, product finders, service widgets, responsive, etc.,
On the marketing part, there is great opportunity to better market your products and services to new customers. SEO can be updated to include new search terms. Improved marketing plugging, and social media features can be added during the redesign & development of your website.