It is a good place to start.

I disagree. Reddit's UI is a terrible place to start for a social media site. Reddit isn't popular because of it's design and functionality. It's popular because it has been around for 11 years and has served as a link-spamming site that has been able to build up high SEO due to its linking/voting functions. It isn't popular because it's appealing and has a large user base. Its "popularity" is based on visitors, not users.

Regarding the multiple front-end sites - there is some of that on the way...