How about we just nerf Kishin instead of removing it entirely, but buff spawn rate accordingly so that using Kishin would get the same results as right now? Win win, people with Frenzy/Kishin mules don't lose months of work and noobs with no Kishin mules get some benefit.
So you know how when you hit an enemy or take damage, a number pops up? Well that gets super duper annoying when you're trying to boss and you can't a boss's animation, especially if you're playing a fast class such as literally any class with a Hurricane Type Skill and any class with melee Hurricanes as well. This would help making bossing easier as you could see, for example, if Hilla is gonna summon something or blast you with fire.