In the 3-team format, most players either preferred deathmatch or objectives. Those who didn't like objectives could treat every game as a deathmatch, putting the objective players at a disadvantage. The combination of small team size and 2 enemy teams contributed towards this problem.
In the 2-team format, you can treat every game as a deathmatch while still helping with objectives. In 4v4, the maps are so small that you're mostly deathmatching anyways, even if it's Domination or Crazy King. In 8v8, the maps are small enough that you can easily fight on or near the objectives. Since there's no 3rd team, any enemy killed reduces the other team's ability to win the objectives.
So I think this is a win for the new 2-team battlegrounds.
PC NA