OMFG OMG OMG This is super hella cool awesome!!! This is exactly what the Free software social movement needs! Most of the people I know have phones, but no computers (most working class people don’t).
For end users like me the Freedom comes first. Why the hell else would I care about nerd shit? (sorry, ‘lovable’ nerd shit ;)) Sure I’m very thankful to people who are into technology and make cool Free softwares for me, but it’s all about the Freedom. I don’t want non-Free software and avoid it where I can. I don’t think it’s a walled garden any more than Trisquel or Debian sans non-free repos are walled gardens in that the reasons and motivations for unavailability of certain apps are different then why most walled gardens exist (good for society, not hoarding like others) .
As well, from their page:
Will you have a calendar app, maps app, notepad app, etc. by default?
Our first version will be focusing on phone calling, encrypted communication, and web browsing. However the free software community is encouraged to test, port, author, and get involved to take all the great free software applications that exist already and make it work on a 5″ screen.
So let’s see who steps up.
Yeah, it would probably suck as an open source phone, but hey, it’s not an open source phone; It’s a Free software phone 
Also, they got Garrett!
//edit: Ok, I stepped up in the one way I actually can.
I think this is really important and it has a good chance of succeeding because it’s not like all the other times. It’s not tech lust; It’s altruism and love 
//edit: Oh hey, they also have a ringtone contest where you can win one (you just have to scroll way down to find reference to it)