I think Symmetra does need some sort of change though. I don't know why she is even in the Support section, for instance. She should be in the Defense section, because while she is more supportive in nature than Torb, she isn't really Support enough to be actually a Support, and especially not as a replacement for any other Support (looking at you, Team Tips!).
Her shields don't have that much of an impact, and her teleporter is a less reliable Mercy rez (since it can be destroyed).
I think if I had to change Symmetra to make her more viable, I'd give her this:
- She starts a match with all 6 turrets ready to be deployed, instead of only having 3 charges. This way, you can create your initial defense without being one or two turrets short because of walking out.
- Alternatively, give her some mobility option like a small rocket boost out of her boots when pressing space that allows her to traverse the map a bit faster, reach more annoying places for her sentries to be deployed, and also be able to get to her buildings faster if she feels like they're going to be attacked or they ARE being attacked.
- Make the health her shields give dependent on the base HP of the respective character. 25 shield points can be a life saver for a Tracer or a Zenyatta, but for a hero who is in the middle of things and soaking up damage, like a tank, those 25 points generally won't matter. Having 50 or 60 would make a difference though.
- Have her be able to recharge her ultimate when it is deployed, but only if it is actually being used. Have it be 5% for each use, so if all 6 charges are used, she has 30% charge for the next teleporter, or if it gets destroyed early, she'll at least have a small base to go off of.
This way, I think she would be a lot more valuable as both a Support character, and generally. She'd still be easily countered by plenty of characters, but she would at least have a lot more impact, especially in higher level play.