Do the Orange Stars indicating a legendary drop appear on the quick (TAB) map?
Last time I checked, all of the markers that appear on the minimap also appear on the tab map overlay. So I would expect this one would too.
Edit: Source: http://www.diablofans.com/forums/diablo-iii-general-forums/diablo-iii-general-discussion/31191-officially-impossible-to-miss-legendaries-now
Confirmed they do show up so people don't miss them.