Playing it is one thing, posting about it on the forums is another.
I'm sure a lot of people play Overwatch too but the posts in that section are also lacking.
As a general rule, a new section for a game will be added when the 'General Game Discussion' section beings to become dominated by posts from that game (as was the case with overwatch).
As of right now there are only 3 rust posts so this will be denied.
Also this doesn't mean spam that section now with rust post and make this suggestion again.
As for TS3 channel, ask an Staff/Global and they can make 1 or 2 public rooms for it.