Honestly, i'm a bit tired of playing referee in this ping-pong game. I've opened a thread out there already:
It's got positive feedback, and the Signal people made an APK publicly available in response. It was a huge step. The next step is to open some forum post specifically about F-Droid.
But at this point, I'm a little tired of being pushed around by both sides. I know the issues, and I have zero control over either side. So I'll let other brave souls submit themselves to this over at OWS. At this point, I scratched my own itch: there's a non-Google-Play version available that can self-update freely. I'm using it, it works. Apparently, it's supposed to work without GCM, but that's not really working yet in my experiments, so I've given up on that for now, but I was hoping someone else would push this again.
Hopefully someone will pick up the flame.