Game Director Jeff Kaplan of Blizzard has indicated changes to Symmetra are coming soon to the Overwatch PTR. He recently revealed in a developer update on Blizzard's Youtube Channel, along with some other developer updates as well. Their goal is to make her less of a situational character, and a more fun dynamic character to play.
Symmetra, the support character without a heal, has always been in a strange place in the Overwatch community. While her turrets could slow enemies down and her teleporter was great on the first point, other situations meant that she was running at a reduced effectiveness. Kaplan explained that they saw the ultimate ability was one of the main causes of this, as her teleporter effectiveness was strongly reduced on the second point.
For the first time in Overwatch history, you'll have a choice of Ultimate. While her teleporter is still an option for those who want it, she'll also have a choice of a shield generator. As Kaplan goes on to explain: The shield generator is a built object that gives shields to all allies in a large radius, that goes through walls. It's a destroyable object, so Symmetra has to protect it.
But that's not all. The teleporter itself has gotten buffed, getting a buff in health, but more importantly, shields. One of the biggest problems with protecting the teleporter was the inability for Symmetra to repair the teleporter if it was at low health, meaning that it was going to go down. Now with the shields, some of that health will be restored, meaning that Symmetra can protect it a bit easier going forward.
The other big change is that her ability to give shields to her comrades. As Kaplan went on to say, that ability felt like a chore for most players, and wasn't as interactive as they wanted it to be. So that ability has been eliminated, and in its place Symmetra will be getting a Photon Barrier. Similar to Reinhardt and Winston's barrier: Symmetra can push a barrier in front of her which moves forward after using it. While they didn't show an example, it sounds like it will push forward at a steady pace, allowing you to follow the barrier. This may give Symmetra some aggression options that she didn't have before.
As for her Turrets: the ability's cooldown and timing has changed. Previously she would have to place 3 turrets and then wait for the cooldown to place an additional 3. Now, she can just place all 6 in a single run of the ability and allow her to recover faster if those turrets all go down in succession. A slight reduction in the cooldown (from 12 to 10) for the recovery of turrets as well.
Her weapon gets a slight distance buff as well, but it's only a small boost. Her weapon otherwise functions the exact same.
Beyond Symmetra, the mentioned Oasis map during BlizzCon is coming to the PTR very soon as well, with a goal to have it out of the PTR and live in early 2017. It'll come after Symmetra's changes. In addition, they've added a button at the end of the match that allows you to group up quickly with the group you just played with.