The problem is not her being equal to the others. the problem was that is all the stories about her being Jesus' lover...
I think it is definitely possible to separate the status of Mary Magdalene being recognized as an apostle versus her being the lover of Jesus.
The story of Mary Magdalene being a prostitute is not in the Bible, and is probably a much later invention of people combining various stories of the New Testament into one narrative. The idea of Mary being the lover of Jesus comes from the Gospel of Philip which is part of the Nag Hammadi gnostic texts. The Gnostics were not part of the Hebraic tradition. Gnosticism is an entirely different religious tradition that tried to hijack Christianity (as well as various other religions) to promote their own religious ideas. "Gnostic Christianity" is thus outside the teachings of Jesus and the early Church which is why it was rejected entirely as heresy.
That and similar texts which suggest Jesus were made all seem to date several centuries after the four canoncial gospels and the establishment of Christianity. With the texts dating within the few decades after the death of Jesus, we have zero evidence he was married (to anyone). Personally, I view all the gospels written after John to be equivalent of fan fiction. Just because some bored housewife has written erotica involving Kirk and Spock doesn't mean they were lovers during the original episodes of Star Trek.
Was the idea of Mary Magdalene being a lover of Jesus even in the popular imagination before the discovery of the Nag Hammadi manuscripts in 1945? To be honest, I don't know - but I suspect not (although obviously there was a small group of people in the 5th century or so that wanted to believe so, but they were outside the mainstream of the Church).
Anyway, if Mary Magdalene is determined to be one of the disciples, this is likely to occur very early in the Christian Church. The ability of women to become priests and bishops will probably happen, but anything more has little basis.
Mary Magdalene completely disappears from scripture after she witnesses Jesus return from the dead. What happens to her afterwards is never mentioned. Given her obvious prominent role before that, it makes for easy speculation, but in the end we are left with no evidence on what kind of role she had in the early church. For her to become one of the apostles, the world would need a lot more evidence of her role in building the church so that her role in it can be considered a role model and example of the future.