The problem isn't the rifle nade. Ever since the Nerf it doesn't have the damage it had before. Before even if the unit is not clumped up it could still deal a decent amount of damage. Now if you use rifle nade on a unit that is not clumped you kill one model and deal slight damage to the others. If your unit is clumped up and gets hit by a rifle nade and wiped out that sucks for you.
Only the rifle nade's cost was changed, nothing else. It still does as much damage as it always did. Soviet weapon crew health got buffed but that's it.