Originally Posted by
Ashkendor
This is already a thing, just most people don't realize it. Most mobs won't aggro on you if you're out of their LoS, but there are exceptions. Walk past a Mudpuppy/Ninki Nanka sometime. Seriously, walk right in front of its face. They can't see you, so they only attack if they can hear you (i.e. you are running near them). I think Morbols and a few other things act the same way. Mobs in the Diadem aggro on you when you get in range whether they can see or hear you or not, so arguably they aggro to your smell.