I doubt adding or changing the primary content of the page would get your page ranked higher - as the page already has content, and further changing that would change the metrics/algorithm in the process, which is unpredictable and non-measurable.
But updating content in terms of having people participating on the comments section (which is located below your primary content) - then yes, as that can be translated to higher user interactivity/user engagement, which signals to the search engine that your site is having some valuable content, and is engaging the visitors to further participate on your site by submitting comments, etc.
Consistently changing your meta-description (or automated updates by SEO plugin/tools), will also contribute to the first scenario ^ , thus, I doubt that would be good.
Otherwise, if your pages are all stuck in 4-10 on the SERP, another way would be to boost your site's authority by having very high quality links from news sites, etc, as those would gradually improve your site's authority, which is synonymous with higher ranking in the process.