Things that still haven't been changed in years
Siege breaking is impossible if you aren't ziggs or syndra or xerath
Inhibitor turrets are still weak as fuck
Mobility power creep
Power creep
Critical strike chance is still RNG
Split pushing is still uncounterable if you aren't one of the ten champions who have global presence (Minus jinx)
Ranged champions are still retardedly oppressive against melee to the point where you might as well quit your lane if you are a melee vs ranged (Minus bot lane)
This is an open list, feel free to add more.