There are a couple of things that happen when a company does a “redesign” that can impact your ability to rank on Google effectively.
When Over-focus On Visuals Removes Optimization
Since website redesigns usually involve the leadership of the business, this can lead to a lot of input from professionals who do not have training in SEO practices. These c-suite leaders usually have the run of the floor, and this can lead to large swaths of text being replaced by flashy images, videos and generic “sales type” verbiage can run amok.
“What we do”, “We’re the best”, “Professional Services”, “Find out more”, “Click here” <- All of these phrases might seem like okay headers to a designer, or to a company president. But you should know that they lack the meaning and relevance that COULD be added.
E.g. “We do keyword research” “We’re the best at Keyword Research”, “Professional Keyword Research Services”
Each page/service should INTENTIONALLY include a focus on a particular, researched set of terms and relevant phrases, and have internal links from page to page to reinforce that relevance. This can get lost.
When Technical SEO Basics Are Ignored
Those fancy graphics, videos and parralax effects can end up bloating your site’s load time. Slow loading sites lose the ‘tie breaker” with other similarly relevant or authorative sites, costing you ranking as well as hurting your conversion rate as slow sites get fewer customers.
You also get designers who don’t map out all of the 301 redirects for the previous pages, and you end up with a ton of broken URLs that may have had external traffic or links pointed at them. You might also have someone “throw the switch” on the site, but still have a “no-index” applied to pages or the whole site, taking it off Google’s list of rankable websites!