I'm a little curious as to why this mechanic got removed?

My only gripe with it was that it made targeting enemies a little awkward, however tab targeting more or less alleviated that problem.

I used this as a mechanic to get my bearings to get ready for the next chain pull. It kept my chain going while allowing me to get a few seconds towards my cooldowns resetting. I also used it as a way to see if the enemies not directly targeted were getting weak so I knew when to pull more enemies.

This could be alleviated by having health bars above the enemies head, or to make them "cower" if weak. Cowering could slow/weaken their attacks or throw them into a short fear.