The tank/engineer changes are really bad for Breakthrough
Unless the person driving has never driven a tank before or they leeroy it into the objective, they're nearly impossible to kill without half the team playing engineer. I don't drive tanks; before season 3, I maybe had a hour total driving a tank. In the last 2 days, I've had multiple games with 60+ kills where I stayed in the same tank all game, taking RPG after RPG like it's nothing.
You don't even need engineers to heal you anymore as long as you have emergency repairs equipped. If you do have someone repairing you, you can be really aggressive with the tanks, because they can out heal someone firing RPGs. Two engineers healing you means you're a god. On maps like Liberation Peak, it feels like it's not even worth trying to kill them. You need to spend all game pelting them with rockets, just for them to be back in a few minutes if you do manage to kill one. The Javelin is the only launcher that feels like it does enough damage to kill tanks, but it's hard to use on maps without open sight lines.
From what I've seen they play better on other game modes, but it's really killing Breakthrough for me, which is what I play 99% of the time.