Pope Pius XII wrote in an Apostolic Constitution, “The scholastic Doctors have recognized the Assumption of the Virgin Mother of God as something signified, not only in various figures of the Old Testament, but also in that woman clothed with the sun whom John the Apostle contemplated on the Island of Patmos” (Munificentissimus Deus).
Note how Revelation 12:2 depicts this "woman" figure as experiencing birth pangs. Also, notice that a part of the curse of original sin is pain during childbirth (Genesis 3:16). The Roman Catholic interpretation of Revelation 12 is weakened because according to official Roman Catholic teaching, Mary was preserved from receiving a fallen nature:
"Through the centuries the Church has become ever more aware that Mary, "full of grace" through God, was redeemed from the moment of her conception. That is what the dogma of the Immaculate Conception confesses, as Pope Pius IX proclaimed in 1854: The most Blessed Virgin Mary was, from the first moment of her conception, by a singular grace and privilege of almighty God and by virtue of the merits of Jesus Christ, Savior of the human race, preserved immune from all stain of original sin." (CCC # 491)
Thus, she could not experience pain when bearing children. But this is clearly not the case, according to Revelation 12:2. "She" was clearly in distress. If Mary was sinless, then she would not have to undergo pain in labor. One may counter this point by saying that the birth pangs spoken of in Revelation 12:2 could be a reference to something painful in the life of Mary such as witnessing the crucifixion of her own Son, but that would be totally speculative.
Does Mary have eagle's wings (Revelation 12:14)? Where in Scripture do we ever hear of Mary going to Egypt to be fed for 1,260 days? What about the fact that the flight of this "woman" took place after Jesus Christ's ascension to God's throne (Revelation 12:5-6)? Did Mary have children who experienced persecution in the wilderness (Revelation 12:17)? The Roman Catholic New American Bible Revised Edition gives this interpretation of the "woman" mentioned in Revelation 12:
"[12:1] The woman adorned with the sun, the moon, and the stars (images taken from Gn 37:9–10) symbolizes God’s people in the Old and the New Testament. The Israel of old gave birth to the Messiah (Rev 12:5) and then became the new Israel, the church, which suffers persecution by the dragon (Rev 12:6, 13–17); cf. Is 50:1; 66:7; Jer 50:12."
The best case scenario for a person who makes the argument that Revelation 12:1-2 supports the assumption of Mary would be one that is inconclusive. We cannot fully grasp every aspect of the symbolism of the Book of Revelation due to not living in the same time and culture of writing. A twofold interpretation of this passage (that the "woman" is both Mary and the people of God) would be unlikely and contrived to put in motion a self-serving agenda.