I couldn't find an existing ticket for this, but I remember it being mentioned somewhere before.
Would like to be able to draw vector shapes on top of a map with various colours / opacity / textures. Bonus points for code that assists with drawing and manipulating the vector with touch events, placing markers on the corners for resizing etc. Otherwise, at the very least some event triggering for clicking + interacting with the vector shape.
This adds a whole other dimension to mapping applications for plotting areas and recording information against these areas.