Two things we've known about for a while now: D.Va was being buffed by Blizzard, and Zenyatta is a bit rubbish. In an interview with GameSpot, principal director Scott Mercer has outlined how both are to be improved in an upcoming patch.
First of all D.Va. Her future form will see Defense Matrix changed to an effect you can toggle on and off. You'll see a meter running alongside the ability which shows how much juice you have left in the tank.
What about Zenyatta? Well he (it?) will not only gain a stronger shield to help with survivability, but will also move much faster whenever his Ultimate is activated. Is that enough to raise this Hero's profile to a competitive level? We'll find out when the patch goes live.
On that note, we don't yet now when it will be released, but we'll update this story as soon as we learn more.