You can still play them in the "variety" playlist, which has through a bunch of different modes.
You might even get more chance to play them now, from what I've heard
I also just picked this game, having a lot of fun with it and the expansion maps are cool too. The 6v6 is awesome and I love the fast-paced action. Pretty decent movement as well, sort of makes up for Brink.
Yeah I like the game. It's fun. Pulling modes during a sale, which is going on to get the game into more players' hands for not having enough players is straight silliness. Things mightve gotten a little better.