Sombra is, by her core concept, basically a support hero, but she can never actually be given the support role because it simply doesn’t fit her. The biggest problem is that Sombra cannot heal and should never be able to heal.
Heroes are created with an identity, and Sombra’s identity is hacking. Most people associate hacking with something negative first and foremost, like hacking security systems. Accordingly, Hack has to be a debuff / CC, and that’s exactly how OW1 players classified it back then when the question came up whether the silence effect should be removed from Hack.
Up until the introduction of the fixed role system, I would have immediately agreed with anyone saying “let’s move Sombra from DPS to support,” because conceptually and based on her original design she was a supporter. But without healing, that doesn’t work—and every way of cramming healing into her kit is awful.
There were frequent suggestions to do it like Ana or Juno, but Sombra’s weapon just isn’t designed for that. It’s an SMG, which naturally has a high fire rate but low accuracy. At range, Sombra would heal basically nothing, while at close range she could easily keep a tank alive on her own.
Healing only through abilities—another common suggestion, usually with the idea that Hack should handle it—also doesn’t work, because every support has to be able to heal without restriction. Supports who have restricted healing, like Brig or Moira, still have an additional alternative way to heal on top of their normal healing.
What would have to happen, and what the consequences would be:
Sombra would have to lose about 90% of her assassin playstyle. A hint of it could remain, but no more than that. Accordingly, Sombra would need to be shifted back toward her utility-focused version, and that inevitably means Hack would need a longer duration.
The current duration with a 1-second silence effect is not sufficient and leaves a massive power gap in Sombra’s kit that has to be compensated with raw damage. If you don’t want to give Sombra damage but want to preserve what makes her unique, the silence effect on Hack would need to last 4 seconds. With adjustments to fire rate or damage—I recommend fire rate—you could then reduce the silence duration to 3 seconds.
Since in 5v5—and only in 5v5—we have the problem that all kinds of debuffs and CC are extremely strong against tanks, Hack would need to have a reduced duration on tanks, just like Sleep does.
Some people will, as always, say: “No, Hack needs to be removed,” but we all know that’s not going to happen.
The only other alternative would be a Sombra who, in addition to her silence effect, also has other debuffs / CC effects. And since in both versions we need something like invisibility—because Hack is very sluggish—and we also need an escape ability, those additional effects would also have to be part of Hack. Unless you manage to create a reasonable form of invisibility that allows us, through a single ability, to both engage and disengage when things get tight. In that case, you’d free up one ability slot for an additional effect.
However, it’s more pleasant to play against something that has one annoying but strong debuff/CC than two different ones at the same time. That’s why the first version with the longer Hack would still be the better option.