Liz, if I have over-generalized and offended, I apologize. Looking back at my post I was probably not as charitable as I should have been.
I've been in several PRotestant denominations (and non-denominations) in my life, and perhaps I think too much of my own personal experience. I do have a tendencey to universalize particulars. But what I have described has generally been the attitude of the churches I have been part of, and that of most of the Protestant Christians I know when I talk to them about Orthodoxy.
Your main question of me seems to be, "Why should Protestants be united on doctrine?"
When I was a Protestant, I would have agreed with you. Now I see things with a new set of eyes and realizing, first, the desire of Christ for His Church to be united in a very clear way, and second, that the Church was united in that way for almost a millennium before it started to break down, and another half before it started to completely fall apart in the West.
The Church must be united because there can only be one truth. The way I see it, every denomination (not to mention the unconstrained non-denoms) can't be right if they aren't in agreement on the core issues - which Protestants are not.
For instance, Apostolic Succession cannot be simultaneously important and unimportant. The Eucharist cannot be Jesus' body and blood and not Jesus' body and blood. You can't die and go to Heaven, and go to Purgatory, and go to Hades. You can't be able to lose your salvation and not be able to lose your salvation.
Sure, we all agree on the need for a Savior, which is a great starting point. THat isn't enough though, in my opinion.
To take another analogy, if doctrine was a multiple choice test with questions on each issue, I see myself as suggesting that each question has only one correct answer. Protestantism as a whole, with no need for doctrinal unity, essentially says that answers A-F are all acceptable, because once upon a time someone decided they didn't like answer B. I can't wrap my head around that.
(I hope I'm not coming across as angry or argumentative. I do genuinely want to understand how you are seeing things.)