Media Server/DLNA
I think a media server application like mindlna would be a great addition to Freedombox and could even become Freedombox's "killer app". This would make leaving streaming services like Netflix and Apple's "iTunes in the Cloud" much easier and more feasible for technical and non-technical users alike. Well, assuming those users are willing to repurchase their iTunes libraries or their favorite Netflix videos on DVD and/or Blu-Ray and liberate them with tools like MakeMKV and Handbrake.
I know it's possible to install something like minidlna without Freedombox, but I think it would be nice if it could be installed and administered via Plinth because A) It would be easier to work with, particularly for non-technical users, B) It would be a way to add this great feature while making it approachable to non-technical usres - which could help to get them interested in something like this, as opposed to scaring them away with very complex and technical setups, and C) It would make Freedombox a little more attractive to technical users who don't want to spend half a day setting up a dlna server.