Mag really needs another look. I think it'd be sick if she took an anti-armor offensive caster role focusing on the neat but underused Shard mechanic from her rework:

• Polarize strips a percentage of enemy shields and armor. Enemies that are fully stripped of their defenses drop Shrapnel (shards) equal to a percentage of their max health. Allies hit by the wave have their shields restored as they do now.
  • No damage is dealt to health, just to shields and armor. Would not be a nuke!
  • Enemies with Robotics, Machinery, Ferrite, Alloy health/armor drop double Shrapnel.
• Mag can pick up and store Shrapnel. Stored Shrapnel provides Mag with an bonus armor, up to a capped amount. This would replace her current (shitty) passive.
• Push is added to Pull, making it 'Push & Pull'. Pull (hold 1) draws in Shrapnel and pulls enemies. Push (tap 1) tosses enemies and throws a percentage of stored Shrapnel out as projectiles, dealing damage equal to the amount of Shrapnel consumed (1 Shrapnel = 1 damage).
• Magnetize can be detonated by recasting Magnetize on an existing bubble, creating an explosion and ragdolling enemies. Enemies can no longer just walk out of the bubble. Damage dealt to the bubble is spread to all enemies inside the bubble. Shrapnel thrown by Push deal double damage to Magnetize bubbles. When a Magnetize bubble has no enemies inside of it, it explodes.
• Crush consumes all ^{or a large percentage} of Mag's stored Shrapnel to deal extra damage equal to twice the amount of shrapnel consumed (1 Shrapnel = 2 damage). Enemies killed by Crush also drop additional Shrapnel.

Basically she rips off enemy armor and then uses it as a weapon. She'd have similar scaling method as Equinox or Nidus, where she's constantly building up her Shrapnel and using it to enhance her powers. Her primary role would be for stripping enemy defenses, with the ability to dish out tons of damage against the enemies she's made vulnerable.