Being able to hack through walls was ridiculous and while the Sombra may have benefitted, it was a frustrating trial in “will it won’t it” for everyone else who escaped her LOS. LOS needs to stay.
On top of that, Sombra is a stealth hero, the whole idea of damage threshold would imply she could be a frontline hero too which kinda busts that whole “sneaky little hearts” narrative.
Could she use some additional help or changes? Yeah, but where she’s at currently should stay in place. Change something else.