Who said anything about lowering systematic damage? They did offer you a solution to reduce damage yourself this patch:
VS
is far more effective now. And any armor on top of it drastically reduces damage even more. At least versus adcs, Tanks should be semi viable again.
We still have to deal with Conqueror of course, but this patch has mitigated one of the problems.
Otherwise, damage is pretty similar to Season 1-5. (With the exception of Shojin users/Conqueror)
P.S. Keep in mind, before the True damage IE rework, Randuin's only reduced crit damage by 10%, so in comparison to what it used to do, it's already pre-buffed