It just me or Kai is just hyper of mobility of assassin + kogmaw damage?

Like honestly + + + can sherd tankers, squishy and everything yet in same time you not able to lock her down and if you do she would out sustain you with her shield + healing? What is the logic of broken method is this? Even assassins can't kill her at all if she buy + that build ? I just love how that she balanced to make it impossible to kill her late game special in 1v1, i feel like she outclass all other adc either in damage or mobility.

And other note, what is wrong with riot giving every new champion some sort of shield ? like why adc got shield , adc already because of their high AS+ the new broken rageblade = alot of sustain.