I can’t count the number of times a party member has run past a heart after an enemy has died, because they are barely discernible from the ground clutter.
They also don’t notice someone clicking on one, because it disappears and then takes 5 seconds to materialize the new mob.
Hell, I’ve skipped over them at this point because I can’t see them in all the mess and stopping to mouse over everything to find one just takes up too much time. Not to mention they’re not at all recognizably different than a normal elite monster, or the like.
They need a bright glow, animation, and or sound cue so people are alerted to their presence. Then they need a speed up “summoning” animation because its absurdly slow.