The rules aren't changing, they're being applied.
Just so we're all clear, a man upon ordination to the diaconate (which comes before priesthood, of course) incurs the "impediment of holy orders" (1983 CIC 1087) meaning that this priest cannot marry his intended in the eyes of the Church; not ought not, but cannot. Moreover, if he does attempt marriage, even a civil marriage, he will be automatically suspended from ecclesiastical office (1983 CIC 1333, 1394) and sets himself up for additional penalties, up to and including dismissal from the clerical state. All of this would need to be addressed separately from his excommunication, which was apparently incurred for other activities.
Maybe it's just me, but I sense today a rather different mood among American bishops facing outlandish behavior by their clergy; problem-priest cases seem much less likely now to drift along year after year in unresolved, canonically ambiguous states. Ecclesiastical justice is never swift, of course, but at last its wheels seem to be turning again.