And that does not make the FF/SU-85 specialized. In order for this units to be specialized vs super heavies they would need high penetration low accuracy (they already have high penetration).
No, existence of these alternatives does not make FF and SU specialized.
Their much higher penetration and lower rate of fire, designed to combat slower or highly armored vehicles is.
Accuracy does not play as big of a role, because target size affects all incoming shots, that includes ATGs, which need to combat both, med and heavy armor without 100% accuracy on both and same goes for handheld AT.
And making units which are end of tier and capable of fighting reliably exclusively 3 axis units(taking into account your accuracy thing, which would make them unreliable against meds), which can engage a wide range of targets is utterly retarded idea to even think of.