I get your point, I did not know that the accuracy became worse after the patch (haven't played Sovs for a while now), but imo the pen and accuracy was extremely good before as well.
The thing is that it has to be bad in some way. It perfectly counters Light Vehicles like 222s. 251s, Flak HTs and Luchses by killing them or at least forcing them to move out of an area. The barrage then is just a nice bonus. It being free was a problem in the first place.
If you want to get a sniper tank hunter, you get the SU85 (which also has its flaws, but still).
well the pre patch SU-76 at least had fire density... a really high rate of fire.. to make up for its awful accuracy... sure it missed alot of rounds but it could fire them fast enough that missing doesnt really hurt the tank destroyer...
as per light AT... yes it counters 222s/luchs provided it has at least 1 conscript supporting it... and rushes to medium-close range so that it actually manages a hit... without 1 conscript supporting it... it is theoretically possible for a luchs to kill an SU-76 thanks to a combination of its lack of accuracy slightly slower speed and lack of a turret...
and yes in terms of AT performance the SU-85 is far superior...