No, there seem to be a lot of people (or at least outspoken people) that aren't terribly thrilled with their implementation. I personally don't care one way or another if the monsters are flagged as aggro monsters or not, but I do think the icons are remarkably obtrusive.

A suggestion I saw somewhere else, perhaps on a fan site forum, was to just put the icon with the Difficulty icon that pops up when you click a monster. That'd be the best way of implementing it as just a marker. SE could get a bit more creative with it, perhaps making aggro monsters display certain obviously aggressive behavior or otherwise integrate that "this guy will attack you without warning," sign into the game in a more natural, less tacked on way.