In a recent discussion of the ending of Mark’s Gospel on X-Talk, it was suggested that having Jesus himself appear to the women, after his appearance has been promised through angels, is redundant, and I agree. But this is precisely what Matthew does to Mark’s narrative, i.e. create a story with precisely this redundancy, and this itself needs to be explained. It perhaps suggests that Matthew knew a story significantly different from Mark’s, and this was the best he could do to weave the details of the two together.
Mark’s story, on the other hand, does not merely promise that Jesus will be seen. It tells of women who are to deliver a message about Jesus being seen in the future, but they do not deliver it. The narrative of Mark, as it now stands, leaves the reader wondering whether the disciples ever saw Jesus in spite of their not getting the message.