Seo Concerns With 4.3.5 Compared To Older Versions

We just upgraded from 2.x to 4.3.5 and our SEO expert is very concerned with changes in the code that will impact the SEO. See his concern below. I would appreciate any feedback. Are these legit problems with 4.3.5, how to fix?

'The "issue" - The old cart places the DIV containing page content (product description, image, reviews, etc) above the DIV that contains the navigation and form items. This is generally considered beneficial- to have the actual content unique to that page physically at the top of the file.

The new version has the reverse orientation. You will see the unique page content is actually at the very bottom of file. Navigation and form elements are placed above. Generally this is considered less ideal."

We are using the default responsive theme.