I don't think that many Latter-day Saints consider the term Mormon to be derogatory. It is after all, the name of an important prophet and is still part of the official name of the Church's most prestigious choir. For many years the nick-name "Mormon" was embraced and was even featured in television advertisements for the church. However, in recent years the Church has officially discouraged use of the term Mormon to refer to the Church and its members in favor of the official name, the Church of Jesus Christ of Latter-day Saints for the church and Latter-day Saints for the members.
This move away from the term "Mormon", seems to stem more from a desire to show deference to the official name, which Latter-day Saints believe to be divinely inspired rather than a dislike for the term "Mormon".
We've been discussing this on Church of Jesus Christ of Latter-day Saints/Talk.