So after Vakinox mentioned putting up some screenshots on Pixel Joint for critique I went to their forums to see what I had missed in the long time since I last visited it.

Well! There's a thread for a free image editor PaintCAD (apparently a port of a mobile Java app, but that's irrelevant). A particular feature of that editor is a tile editor, the screenshot of which overlaid tiles' indices over the tile images themselves.

I think this is a good idea and would like to see this implemented with a toggle on any/all Sphere map editors, maybe even similarly on spriteset editors and possibly animation (MNG) editors.

I definitely would like to see this on spriteset editors!

One heck of a feature request!

Question - for the map/tile number overlays, would you only show the active layer's tile indices or would you find some way to show the entire tile stack for a given X,Y?

Good question. Possibly only the currently selected layer. But I might do something with mouse hover.