The changes to her sentries is amazing. Having 6 charges, instead of 3 will be really good for initial setup, but also when you need to move them, with a recharge of 10 secs you can move all 6 every minute.
Having your nest be at a different place every minute could have a big impact on the opposing team...as they would have a hard time predicting where you set up...and very often the first encounter with Symmetra's sentries ends up being a major delay, or a wipe if it was a team push.
Being able to put them back up faster once destroyed, will also be annoying.
The shield generator sounds interesting, but remains to be seem how large of an area is covered. He stressed a few times that it's really big...so I kind of expect to be surprised by the range.
The barrier sounds cool, will have to see it in action to really know. How fast does it travel? How far? How much HP before it's destroyed? How big is it? etc...
A slightly longer range on her primary is also pretty big, it doesn't have to be that big to make a big impact. She can hurt people a lot when fully charged.
As a Symmetra player, I love these changes. I try to play her as often as I can on map where she is good, and usually switch if we lose the first point.
In Competitive, I usually only play her on Hollywood, Hanamura, Temple of Anubis, Volskaya Industries...on point A only. In quick play I'll sometimes play her on King's Row, Dorado, Numbani, and Route 66 at the start.
I would be happy if I could play her on more maps, and not just on point A.