The web-application is a custom-built CMS which has several sub-applications and each one of them has code and content residing in the same directory structure. Due to the a
First, I don't agree that Git is inappropriate for non-technical users. Yes, there are certain features that newbies won't use (e.g. git-send-email). But there are also GUIs like TortoiseGit to make simple things simple.
However, I think you're approaching things the wrong way. Basically, you have content that will change frequently and needs to be editable very easily by Joe Bloggs, and code that will be modified less frequently by coders. The traditional solution is to use a real CMS (e.g. Alfresco, SugarCRM, Drupal, etc. or a Wiki (MediaWiki, MoinMon, etc.), with optional plug-ins. Keep in mind, wikis (and most CMSes) allow versioning of content, in a "user-friendly" way.
Even if you must keep your in-house code, I think you should still want to extricate the content so they can be treated separately. Once you have the code and content separate, your repository will be a more reasonable size. Then, you can use whatever VCS you want (though I'm not really sure you're right that Git is inherently bad for large repos).