Based on player feedback from the last round of Overwatch Beta Action, where it seems that it was all like, "Yo Blizz, Point Capture and Payload totally rock the mic like a dope MC, but we want more!", it looks like Blizzard has taken all those comments seriously. Which is why the next round of Overwatch Beta Action has been pushed back to sometime next month. To make way for a new as-yet unannounced game mode. Plus, some new maps.
The official update and reasoning was posted on Battle.net by Game Director Jeff Kaplan,
When we brought the Closed Beta offline last December, we did so with the intent to use the downtime to address player feedback, work on some core features (like progression!), and adjust the balance of the game. Our goal was to have all of that work completed before bringing the Closed Beta back online, and our hope was to have that goal complete by middle to late January.
While progress has been great and the team has been working super hard to get everything implemented on time, we're not quite ready to bring the Closed Beta back online just yet. We’ve been pretty open about the fact that we could slip into February from the beginning, but a big reason for this delay is that we really wanted to add one more big feature to the next beta patch.
After looking through all of the feedback from last year, one of the things we noticed players consistently mentioning was their desire for more game modes in Overwatch, in addition to Point Capture and Payload. Without getting into specifics, we are working on a new game mode. And we’re very excited about it! And we have some great new maps to support it, too, but we need a little more time to get everything just right.
As to what exactly the new game mode will be, all we can do is speculate. Perhaps Blizzard will take another page out of the Team Fortress 2 book of "Perfect Multiplayer Design" and introduce a co-op horde style mode of sorts. Who knows.
Overwatch is still on track for release across PC and console later this year.