Damage is too high because Riot overloaded assassins and now everyone has to be an assassin
Assassins and the assassin update are the sole reason for damage being out of this world ridiculous. Since Riot decided to give every assassin multiple dashes, multiple forms of cc, multiple escapes, and just generally overload the everloving shit out of them now everyone is in an arms race to see who can one shot the other the fastest. Since assassins were given the means to literally one shot every class of champion with little to no counterplay (and make no mistake, assassins are the premier class in the game right now just look at any sites tier lists) Riot's "fix" to the issue of assassins is to make everyone an assassin.
It's horrible game design, but blame assassin players. This is what they wanted so this is what they got.
with dashes, invisibility and insane amount of dmg,
with zhonya and his E impossible to catch him while having stupid amount of dmg,
who doesn t even need ult to kill you etc. Is not enough that they got stupid amount of dashes and so on that allows them not to only kill you but disengage safely waiting few seconds for their CD and ready to go again, they also have CC, invisibility and so on. Stupid game design. Remember when everything was about outplaying your enemy? Now it's just oh I pressed R or smashed QWE, that s all.