My thanks to everyone for their replies. I have had less time to attend to this thread today, so I am unable to respond to everyone individually. Instead, I'll just say a few general things.
First, I understand the sentiment behind comments along the lines of, "If you believe in a Supreme Creator of the Universe, why doubt the Dormition traditions," or, "If you accept what happened to Philip in Acts 8, or to Elijah or Enoch, why doubt the Dormition traditions?" However, I have to emphasize again that my concern is not primarily that I doubt such things -- they seem to me to be possible. My concern, instead, is more like this: not everything that seems to be possible is a matter of dogma, so why exactly is this dogma (if it is dogma; I am still not entirely clear on that) rather than theologoumena? For example, it is also possible that the Apostle Paul was lifted bodily into outer space (or, to be less absurd, into the third heaven), but it is not dogma that he was. Now, if I were to ask someone, "If you believe in a Supreme Creator of the Universe, why doubt that Paul was lifted bodily into outer space," or, "If you accept what happened to Philip in Acts 8, why doubt that Paul was lifted bodily into the third heaven," these questions would not give the person any reason to actually think that Paul was lifted bodily into outer space of the third heaven, and certainly not that it is a dogma that he was. Likewise, while one might certainly accept that it is possible that the Dormition traditions happened as they did, and might admit that similar things happened in other parts of Scripture, those facts themselves do not provide any particular support for the Dormition traditions themselves, or for holding them as dogma rather than theologoumena. (I know that one of you who made this kind of argument already noted that it "misses the point," so I acknowledge that.)
This, I think, provides some insight into the answer to the question that one of you asked: "Why do people get so worked up about this stuff?" The reason is that it is important. Why is it important? First, because, if things happened as described, then these events reveal an important truth about the Mother of God and about our own eventual salvation. Second, because it is important to know what a Church actually teaches, so that one can assent to its teachings, and so that one can avoid heterodoxy/heresy. Does the Orthodox Church teach as a matter of dogma that the body and soul of the Theotokos were taken into heaven? (Most here, though not all, seem to think "yes," although the answer is ultimately still not all that clear to me.) What about the rest of the Dormition traditions? Is it heretical, or heterodox, to not assent to every detail? Similarly, as someone else mentioned, what about the tradition that Mary lived in the Holy of Holies? Is that something that we must accept on pain of heresy or heterodoxy? What is a theologoumena and what is not? I am still not clear about this.
These questions can also be important because they are relevant to determining what Church is the true Church. This is something that some of you have said is the "main issue." I agree. It might seem to someone -- note, I am not saying that it seems this way to me; I am only giving an example -- that the early Church did not teach, even in nascent form, anything about the body and soul of the Theotokos being taken into heaven. So, figuring out whether the Orthodox Church teaches this may be part of figuring out whether it is the true Church (I mean no offense!); if it is only a theologoumena, then that particular obstacle, if it is an obstacle for someone, would be removed.
Thank you again!