Protestants differ somewhat among themselves, of course, as there are so many versions of Protestantism. There is considerable emphasis upon freedom when it comes doctrine, especially among mainline Protestants. In their Bible study groups individuals express conflicting views on various theological matters and no one blinks an eye. There is little sense that all members of the group must think in lock-step fashion, must all agree. In Catholicism such differences in viewpoints would likely be treated as heresy. Among mainline Protestants there is enormous tolerance for such diversity. I think it was John Wesley who said something like this when they tried to get him into theological debate: "If you love God as I do, if you seek to serve God as I do, let us join hands and walk together."
My own view (and I come out of a mixed religious heritage) is that Christians should have a choice when it comes to doctrine, including their attitude toward Mary. I know that many Catholics find comfort in their devotion to Mary. She has become for them a warm and loving spiritual mother. Fine.
However, I do believe - as stated in an earlier post - that Mariology evolved over the centuries, and that there is little in scripture to justify insistence upon certain beliefs. For example, was Mary the only sinless human being in all history? Nothing in scripture even vaguely suggests that. Was she a perpetual virgin? Nothing in scripture insists on that. Was she the only person conceived immaculately? Well, actually I have always found the concept of original sin as unfair to newborns, so I suspect that all babies enter the world within sin. But nothing in scripture seems to suggest that Mary was born differently from the rest of us. Actually, her parents aren't mentioned in the Bible, but in non-canonical material rejected from the canon. And the Assumption? Not a word in scripture suggests that either.
These doctrines were formed out of theology. If Mary were the Mother of God, therefore this and this and this.These doctrines are seen as logical derivatives from the concept that she was/is the Mother of God.
Now, as to Mother of God. Frankly, it's a matter of words. She was the Mother of Jesus, yes. But, did God really have an earthly mother? Jesus had a physical mother, true, but that part was not God. That was not his divine nature. Agreed-upon Christian theology tells us that his divine nature certainly preceded his earthly appearance as Christ, and did not come from any human being - no, not even Mary. She was the vessel, if you will, that carried the Son of God prior to his birth, but his divine sonship was not derived from her. To say that Mary was the mother of God is one thing. Personally, it strikes me that Mary was the mother of the Son of God better reflects the Bible.
None of this means that Mary is not blessed, as scripture tells us. But I have become convinced over the years that the central, even essential, position that she now occupies in Catholic theology and worship is not based on scripture but on a Mariology that goes well beyond anything supported by scripture.
I also have a problem with this popular concept that if one prays to Mary she will, in effect, go to Christ and help get what we ask for. Since she is his Son, he will be more amenable to her requests. Doesn't that sound a bit strained and strange, even perhaps somewhat pagan? Sorry if this offends anyone, but I presume we should speak the truth as we see it. Isn't it like going to Mom before we went to Dad (when we were kids), knowing that Mom was more likely to go along with what we had in mind. Very earthy perspective. I doubt if prayer works likes that. The whole pray-to-the-saints system reminds me a little of going to lobbyists in Washington to get what you want done. If Christians choose to do that, okay. But why not go right to the top and skip the middle man? The whole saint emphasis seems to be saying that these deceased people have special powers - even powers that they can exercise with or over God. Isn't it, in effect, a modifed, quasi-polytheism?
But let's love one another, as Christ commanded. Didn't Paul speak of faith, hope and love, and the greatest of these is love. Yes, it even trumps faith! Doctrine, I suggest, is second place when it comes to true Christian living. They'll know we are Christians by our love and not our theology.