1
(W) Vishkar Quality: Turrets will prioritize nearby enemy heroes, or Symmetra's target if able.
(Q) Deconstruct (Quest): Basic attacks deal increased damage to structures the more siege damage you have.
(E) Fast Learner (Quest): As shields on allies absorb damage, shield amount increases. At cap, shields regenerate out of combat, even if destroyed.
(Trait) Design (Quest): Gather globes to increase shield amount.
4
(W) Top Architech: Increase max turret count by 2.
(Q) Precision: Short range beam gains an additional charge level and long range ball deals double damage to shields.
(E) Reinforce: Symmetra can cast an untalented shield on herself which is 100% more effective.
7
(W) Defensive Matrix: Turret damage is increased for each nearby turret.
(Q) Car Wash: Increase Basic Attack damage against targets being hit by a turret.
(Trait) Weaver: Regeneration continues during combat.
(E) Protection: An extra shield is provided on cast that lasts 5 seconds.
10
(R1) Teleporter
(R2) Reconstruct
13
(W) Home Security: Whenever a heroic is cast, 2 Sentry Turrets are created nearby that don't count toward the max turrets.
(Q) Full Charge: Long range basic attacks deal splash damage and pierce, travelling to their max range.
(E) Corporate Upgrade: Shields can stack up to 2 times.
16
(W) Blueprints: Increase the range of turrets and the range that turrets can be placed.
(Q) Superior: Basic Attacks slow for 2 seconds, beam stacking 10% per level, ball at 30%.
(E) Rhythmic: Nearby ally Photon Shields regenerate constantly.
20
(R1) Two Way Teleporter: The teleporter that Symmetra places can be entered as well to teleport to the Hall of Storms.
(R2) Big Contract: Keeps can be reconstructed, stopping production of enemy siege minions.
(Q) Double Shot: Both attack types will fire simultaneously if the target is in range of both.
(W) Light Bender: Turrets spawn with photon shields, have half cooldown, and max charges now equals max turrets.
I love the idea though. :)