The thing I'm missing the most is that no standard way of making phone calls exists on linux.
We have interfaces for LEDs, NICs, usb pointing devices and all sorts of weird hardware. But making a phonecall is still a serial port with AT commands? and what about muxing gprs? 3G?
Everybody keeps re-inventing the wheel for "their" GUI.
We all need to agree on a lowest common denominator, some kind of dial-up daemon that can do muxing, set up and automatically knows what to do with incoming calls.

I know it can be done with loads and loads of scripts, but we need to agree upon something simpler; single executable, with simple config, something like dnsmasq for dhcp+dns.
It could have a simple shell program that initiates phonecalls.
All GUIs should use the shell program to make calls, and not talk to the daemon direct.
An incoming phonecall or phone status could be a fifo, /proc or /sys file, what ever is the most appropriate.
The config should already explain all sound routing.

This would be a good first step to making all ordinary linux distros part of the phone linux landscape, and therefor paving the way to having access to a proper phone distro.
Gentoo, Debian, OpenWRT etc.
We don't really need a special phone distro if all the programs needed, already exist in ordinary distros.