Ability to search/filter by multiple tags (like Evernote)
As part of Gospel study, I create meaningful tags. Some tags are reflections of what doctrine/principle I have identified (faith, repentance, etc.). Other tags are to identify speakers (RMN - Russell M. Nelson, DHO - Dallin H. Oaks). Others are to identify a type of content (story, testimony, etc.) Other tags are reflective of the venue (GC - General Conference, Liahona - the Church's magazine, Ensign - the old magazine).
Being able to filter by multiple tags at the same time would be incredibly powerful. If I am preparing a talk/preparing a lesson/answering a question and I want to filter through all my previous Gospel content to find General Conference stories by President Monson about the temple, I cannot currently do that, this would allow me to do that.
(This would be similar to what you can do in programs like Evernote, for context.)