So, to answer, why is it bad?
Well, when Blizzard first introduced it it was actually good, even a little too good.
When I first tried it on pts, I was astonished by it’s damage and that it wasn’t really that difficult to aim. I was telling myself that she is a dmg hero now, and she is squisher now, so making such powerful melee would make sense. In reality, what i experienced was a bug. Allow me to explain.
Initially this beam weapon when snatched to enemy dealt 4 ticks of damage per second. Each successful tick increased the charge to next damage level by 12,5%. What that meant in theory was that, once you touched enemy, you had 0.25 second where it did not matter whether you properly tracked enemy or not, and you would only be penalized by how much of a delay you made before snatching the enemy again. That meant that not only this weapon was slightly more forgiving in aim, but also meant that you had almost guaranteed level up in damage after 2 seconds.
Unfortunately Blizzard forgot to give some sort of next delay damage lock out on this weapon. What does that mean? It means that snaping to a target and then off the target reset the damage snaping and you could damage person again within the 0.25 frame window. You could do this by quickly tapping the primary, or shaking the camera to quickly snap on and off target.
If you managed to do this 8 times within seconds, you not only dealt 8 ticks to character, dealing double the damage, but also charged your weapon 50% faster, which is something than most people did not notice.
It was obvious that Blizzard would fix that eventually. But they fixed it in a freaking newbie programming student kind of way. Instead of preventing target to be damaged by the beam within the window frame again, they simply increased tick rate, apparently to 1/20 of a second, so that no matter how fast you click or shake camera, it will not be effective nor resulting in bigger damage. And that alone caused huge problems.
Firstly, this made this weapon more aim intensive, which might not be that kind of a deal for some people. But it is, since you need to have 67% accuracy to deal the same damage as before. That’s a Seagull level of accuracy. However this also made the charge level up rate depending on your aim!
What is the problem?
According to data sites, average primary fire accuracy on sym is 35%.
So let’s say I am just above average. Let’s say, i have 50% accuracy.
Suddenly the 4 seconds to deal maximum damage become 8 seconds. 8 seconds. In a melee range. I already mentioned before that 3 seconds was problematic for her, let alone 8. And Symmetra is EVEN MORE squishy, she no longer has her personal barrier nor 75 shields from shield generator.
Double Clap Clap
It feels as if Blizzard thought that the only problem with this weapon was that it had lock on, so removing that would somehow magically sweep all its problems away.
There is one more problem. The tick rate increase means that symmetra deals now half of the damage to armor, compared to simply 20 damage less per second before the fix. This makes her underperform against tanks, as well as against torb and briggite. This is a problem, since people considered her to be a tank buster when they announced that she can now refill ammo from shields, which is probably only good thing about this weapon. In fact it takes her longer to kill D.Va with 100% accuracy on this beam than with the previous lock on one.