It would definitely have to be designed for the kind of crowd that's never installed Jekyll.
As paleolithic as it sounds, I think a CMS build on flat files would be a lot easier to manage than a CMS built on a relational data store.
If you don't need accounts and personalization, or can just do that all client side, you could simply load balance across micro AWS instances pulling from the git repo and stick everything behind Cloudfront -- all for a few quarters an hour.
