Angelus,
I don't see how the difference with the Donatists referred to in the last paragraph affects the theological position one takes with regard to eschatology. Sure, the Donatists might exclude more people from the true Church, but the theological distinction true Church/false Church remains unaffected for purposes of eschatology. The Donatists would simply be adding more tares to the field, but the tare/wheat distinction still holds without any theological or conceptual distinction for the implicated eschatologies that I can see.
Thanks for the article, I've started reading it.
DR
The Donatists are heretics because they incorrectly drew the line that separates those inside the Church and those outside the Church.
The Donatists basically taught that the
traditores committed a sin so heinous that could never be forgiven, and those
traditores who were clergy had lost their Holy Orders and that those Orders could never be revived, which caused the recipients of the Sacraments from said clergy to be recipients if invalid Sacraments (in the eyes of the Donatists).
Augustine and the Church Magisterium taught that the
traditores may have committed a grave sin, but their souls could be revived by the Sacrament of Penance. And, importantly, that the Sacraments work
ex opere operato, so even a sinful priest could distribute the Sacraments. Also, those Sacraments marking the soul with an indelible character cannot be undone by committing a sin.
According to Augustine and the Magisterium, the only sins that put one "outside the Church" are the sins of "defection from the Faith" (i.e., heresy, apostasy, and schism). And even those sins can be repented for, allowing the person to re-enter the Church. The Donatists heretically expanded that list of sins that put a person "outside the Church." And this expansion had enormous consequences in justifying their schism from the True Church.