Illaoi is Overpowered, has too much in her kit for survival, her soul steal is offensive and does negative effect either way if you get out or not, her ground hit does too much damage, her ult can kill people not even in her reach, including under turret. Yes she can be countered, but you need the entire team to fully understand her kit and avoid everything she does, meanwhile her team is killing your base. Unfair advantage in her favor everywhere you turn.