In January, Overwatch director Jeff Kaplan revealed the Overwatch Experimental Card, an upcoming new mode that will enable players on all platforms to test planned changes. It's similar to the public test realm in some ways, but aside from being accessible to all players (the PTR is restricted to PC), Kaplan said that it will be focused on gameplay changes rather than bug testing. And because it will be part of the live game, progress made in Experimental will apply toward levels and special event progress, something the PTR doesn't offer.

Barring unforeseen catastrophe, the Experimental Card will go live tomorrow. In a new developer update video, Kaplan repeated that the new mode will be focused on "radical gameplay changes or things that we want to try out and get your direct player feedback on," a process that will begin with a change to the role queue system.

Role queueing enables players to select the role they want to play ahead of a match—tank, support, or damage—and then assembles teams in a specific, locked configuration. Currently, teams are made up of two players in each role, but the experimental card will change that mix to one tank, three damage, and two support.

Kaplan explains in the video that the change was driven by an increase in queue time for damage players caused by role queueing, which led to internal experiments with the increased number of damage players.

"This was a lot of fun," Kaplan says in the video. "It was very controversial on the development team. We have very strong reactions for and against this system, and ultimately at around the same time we had also mentioned to you that were going to do this experimental card... and so many players said, 'Why don't you let us try it?' So this is your chance."

A major concern Blizzard has about the change is the impact it will have on "off-tank" characters Roadhog, Zarya, and D.Va, who will undergo "big balance changes" as a result. Kaplan didn't detail the changes but he did say that the changes are not intended for the live game unless the 3/2/1 system is also adopted across the board.

"This is a look into what happens if we decide to make Roadhog the only tank in the match, or if we decide to make D.Va the only tank in the match," he says. "You are going to have some insight into the type of balance changes that we would need to make."

Blizzard will be watching damage queue times in the Experimental Card to see if the change fixes the problem, and as always is also looking for feedback from players. Kaplan also teased some "event surprises" that might be taking place while the Experimental Card is up, and reassured players that what they see in the Experimental Card, now and in the future, should not be taken as a sign of Overwatch's inevitable demise.

"Don't panic when you see this card go up. These are changes that we are unsure of, and that's why we're getting your feedback on them," he says. "It doesn't mean that they're imminently coming to Overwatch anytime soon. It just helps you get some insight into what we're focused on and some of our design process."