Blizzard, stop whatever nonsense you are cooking up let me give you a billion dollar pitch:
Asymmetric extraction BR thing set in Starcraft world:
The map is a Terran colony about to fall to the Zerg. Each match opens with a hivemind getting nuked, turning all the Zerg feral. 100 players drop in, with a mix of Terran players in squads playing a co-op PvE FPS, a handful of solo Protoss players who are basically playing Crysis, and a handful of Zerg players playing an RTS and occasional third person action game.
Each faction has different goals. The Terrans are mercenaries trying to find some kind of loot and extract. The big win is gathering intel to locate a treasure vault and getting in there and back out alive.
The Protoss need to recover an artifact or something. Each one is really strong, can cloak, but they are alone. Or maybe they have a team objective, but by necessity have to split up to win in time.
The Zerg are playing a territory control RTS. They are a new hivemind or whatever trying to retake control and they be spreading that creep. They can gather random weak Zerg to their cause, and occasionally take over a special unit to control in third person.
There is no circle, the Zerg players getting stronger and taking over the map is a player driven timer.
I know that was a tangent, but I just brainstormed Blizzards best game in years while waiting on a class to start.