For me his ults does too much with no counterplay. If you don’t have a mobility option you’re pretty much dead. Shields don’t cover you, the environment doesn’t cover you etc.
The fact that is does 75% of your health as a 200hp character + he lifts you up making you unable to do anything + if you survive that for some reason you have a 2s roots that’s just ridiculous. Like come on, chose one don’t do everything.
And at the same time the rest of his kit is very bad for a “main tank” as he is supposed to be.
Well if we want to make him a main tank that is certainly not something he needs.
On the contrary he’d need much more tanking ability at the cost of less damage/utility. If you Run Rein/Orisa or Rein/Winston or Orisa/Winston you’ll be lacking Damage and overall utility for you team that a Zarya or D.Va (ot even Hog with Orisa) could bring because main tank and off tanks should work together. The issue with the current Sigma is that he has some abilities of a main tank but he also has everthing of an off tank.
I mean just with a Mercy DB him he deals 78 per ball, so it deals 156 if you land both shots. If Mercy DB him while ulting you can increase his initial 50 damage as well so that makes a 65 initial damage so as a 200hp character you’d lose 165hp.
And that is without Orisa’s ult because those stacks meaning with both he can deal 108 per ball do he can basically OS any 200hp character during an Orisa ult if he has a Mercy with him.
And he can be pretty safe either behind Orisa’s shied and pushing bits by bits alternating their shields OR he can also go somewhere else and put pressure on the ennemy team from another angle / getting picks while being fairly safe because of his shield and his DM-like ability that grants him shield on top of that. He should be using this to protect his team but in reality he is better off using that for himself because it is much more efficient and that to me is the real problem.
Long story short : he’d need more buffs than nerfs to make him a real main tank OR just change everything and make him an off tank.
It’s sad to have to make a hero that is either one or the other but every time we had a “hybrid” hero they were either pretty useless or a complete must pick.