Meta is fluid, hero viability also fluctuates with the meta. Remember not too long ago, people said Reinhardt was dead, and now he is basically the cornerstone of meta despite receiving zero changes?
As I said, I understand that Sym is pretty much useless in pro-play because her biggest counter is team coordination. She can receive some QoL changes that makes her less dependent on the enemy team being braindead (I gave my own suggestion list here), and that don’t requires a rework of this scope.
Honestly, I don’t think the rework will be that bad (except by orb changes, that proposition is dumb 
), but they are doing much more work than they actually need to do. Symmetra’s biggest issue right now is her reputation within the community, not her kit.