Amillennialism is a RCC doctrine, Augustine the main impetus behind it. First cousin to other RCC doctrines, such as the primacy of Rome, Peter the first Pope, the Papacy, Mariolatry, Purgatory. Amill goes hand in glove with them.
Protestantism is an ongoing attempt to return to the beliefs of the church of the Bible.
Now if we could get our Reformed Brothers and Sisters to see this we would really be united.