So I just got my little brother into the game and as we were comparing our strategy pages we got into the inevitable argument of which one's is better. At that point I thought... 'Damn, I wish there were some way our teams could fight each other so that I could prove how wrong he is.'
But as far as I know that's not possible unless our teams accidentally find each other in sandbox mode. I suggest to add a friends list to the game where the players could add and then chat or have friendly skirmishes with other players.
And I say this not simply because I want to duke it out with my brother, I think this feature would really benefit the game and its community by encouraging more interactions between players.
1
User already pointed out, that you can play sandbox vs everyone as soon as you know their team ID. Cannot find the topic now, but have the links saved.