Hi community, i hope someone can help me with this, We are migrating our e-commerce site next februari. I'm preparing the content migration. For a large part exact copies of our product listing and product detail pages will be migrated. 
However, we also have a lot of old blog content, which is, because of seasonality and trendiness, outdated and doesn't drive traffic anymore. It actually is just worthless content. (Not only as a traffic driver, this also counts for extremely low to none internal driven traffic (both internal search and internal navigation). We have about 4.000+ blogs of which about 100 drive the most traffic (mostly incited by e-mail and social campaigns and internal navigation promoted on important category landing pages during some period. Is it a bad signal to search engines to delete these old content pages? I.a.: going from a content-rich to a content-poor site?
Off course I will migrate the top 100 traffic earning content and provide proper redirects to them