Yes, Calvin (as was Bucer) did write passionately about no need for the papacy. There is debate still about whether Calvin writings of anti-Christ meant "opposed to Christ" or Anti-Christ - the Beast of the Book of Revelation. I was thinking you were referring to the Beast when most scholars agree (I do also) that Calvin and the Reformers who called the Pope (Paul III and his predecessors from the 1054 schism/split of East and West) "anti-christ," had a small "a" applied, meaning opposed to Christ, the Groom of the Church.
Regardless, there is no meaningly debate at any level of theology as to whether RC's are Christians because they affirm the 7 doctrines (and more) of Christianity.
RC's are heterodoxical meaning they have added to the doctrines of the Christian faith which theologically speaking is not out of bounds.
Out of bounds is taking doctrines away and saying you're the same. That can't be.
The core of Christianity is enveloped in layers of Roman Catholicism is what I learned during my 8 semesters of non-denominational seminary studies.
RC's have indeed elevated the position of the episcopoi (overseer) found in the Bible and as Protestants we would say that no believer has any righteous rank above any other in the eyes of God.
The levels of leadership in the biblical writings are deaconoi (deacon), presbyter (elder), and episcopoi (overseer).
The Patristic Fathers, including Cyprian who was the first to elevate a Bishop as the overseer of other bishops, for the most part wrote of EVERY Christian being not par with each other.
There was leadership.... but the Patristic Fathers's wrote of no "rank" per se, in the kingdom of Heaven, other than of course the Lord Christ begin given authority above all things, because of the Cross.
For those of us who enjoy history, there's no finer history than theology. It's rich, full of conflict because people are people, and it simply keeps plodding along.
Until Christ returns again.
Gotta love it.
Blessings brother Posco!
Mark