Sigma needs to be a reasonable main tank to be paired with Roadhog or Zarya if he is to move out of his 38% GM winrate without bringing back double barrier. To do this, he needs more survivability without buffing his barrier so he’s not overwhelmed so easily. Since most of his strengths (the oneshot rock combo, his uninterruptible ult, his barrier that is now clunky and weak) have been nerfed out of him, it’s time for the backbreaking weaknesses that make him so easy to counter to be worn down too.
-500HP base. 350HP, 150 shields. He’s still more fragile than Rein and Orisa because he has no CC mitigation and no armour, but he doesn’t die to a stiff breeze any more. Now that his barrier is worse and Kinetic Grasp is still on a long CD, he needs to be better at tanking damage if he’s supposed to be a main tank.
-Let him use Kinetic Grasp during his ult animation, like how Genji can use Deflect during Dragonblade. He needs to be able to be caught out by things like Roadhog hook, opposing Accretion and attacks from angles he can’t see coming but still have some sort of self-defence. If you get grabbed by a Sigma ult the correct play should not be “pop Deadeye and 100-0 this tank who cannot fight back or escape before he dies, cancelling his ultimate that took four hundred years to charge and did 50 damage”. With that you’ve actually got to try to outplay him during the ult rather than just get a near-free cancel if you’re paying attention.