in WoW it was addon, not in-game feature, so i don't think that there will be in-game one... but i wonder if there is a way to make our own addons and if so, if there are some already
WOW has build in treat visualization (no add-ons needed).
Top part of the image has default indication: percentage and the glowing red border (it becomes red when percentage becomes "100%"). This values independent for each enemy you select while in combat. Also if your own portrait has red glow, then at least one enemy focusing you.
I find this way of indication useful and simple enough.
A threat meter would be nice for some encounters, but it would likely be more effective to have "threat bars" atop each mobs HP bar so that you aren't having to focus on the far side of your screen/use an ugly graph like that to see your threat.
Comments
Top part of the image has default indication: percentage and the glowing red border (it becomes red when percentage becomes "100%"). This values independent for each enemy you select while in combat. Also if your own portrait has red glow, then at least one enemy focusing you.
I find this way of indication useful and simple enough.
A threat meter would be nice for some encounters, but it would likely be more effective to have "threat bars" atop each mobs HP bar so that you aren't having to focus on the far side of your screen/use an ugly graph like that to see your threat.