Ya, the CDD group has been dead for years. The two big problems with it were that it was just a microcosm of the community itself so no one could ever agree on anything and that alex mostly ignored it. The only two suggestions that I think were ever even partially implemented were spy counts and damages being hidden (in 2015) and the resistance mechanics (in 2016, a year after they were proposed). It's literally been dead for over three years with the only posts being me bumping a dead thread every few months about showing alliance trades in the global trade interface and highlighted green.
Honestly, forget the idea of any sort of closed council or whatever you're thinking of and just post in the suggestion thread. If tons of people like it then just ask alex for his response/opinion. Literally the best option when it comes to suggestions.