Well, I say Eye-Candy, too... it makes an editor great if there's the possibility to produce real looking cities and landscapes with eyecandy, while generic and object-less landscapes make the editor quite mediocre.
A personal example: At MWD, we have some good triggerers, but also two guys who are
excellent at doing eye-candy. They can do things with the AoM editor I never had imagined (just found myself looking at a full-blown greek city with Thermae, rural suburbs, port and theatre today - everything done by combining objects in unusual ways), and that is what makes their maps look great, though their triggers are average of even below (we do cover this by having good triggerers doing the triggers, so expect some great things to come out in the future...

).
But what I wanted to express is that their maps really come to life through the eye-candy and you can imagine to live in the story. That's why I (as a triggerer) think that eye-candy is very important. Second would be good triggers for me, because simple things like renaming units gives your stories much more potential (word?).