they decided to hire an in-house marketing manager, who is insisting that we move the newer domain (www.companynameseparateproduct.com) to become a subdomain on their original site (separateproduct.companyname.com). Our team has argued that making this change back 6 months into the life of the new site will hurt their SEO (especially if we have to 301 redirect all of the old content back again, without any new content regularly being added), which was corroborated with this article. We'd also have to kill the separate AdWords account and quality score associated with the ads in that account to move them back.