Something that needs to be done in preseason that i've heard no one say so far

Revert % pen from Total to Bonus. This change was honestly a terrible mistake for Riot to have done. This version of pen invalidates defensive completely, and is why Mages do f-loads of damage even if you stack MR. Its also the same reason why it feels like armor doesn't exist. Funnily enough, there is only one champ in the game that still possess the stat: Yasuo when he's R'ed.

Reverting it allows tanks to retain their base stats, giving them some extra beef towards the late game so they dont die at the same rate as a squish. This also allows for the % number to get increased if its not enough, and any resist abuse cases can easily get nerfed if they are out of line. Also, by reverting % pen back to bonus, any champ with % pen in their kit immediately goes back to % bonus, meaning that nasty crit Garen wont spin all of your armor off in a second.

Allowing % pen to break through base stats is not what the stat was made for. It was made so you can punch through resist stacking more efficiently, not outright invalidate resist existence and others since guess what, base stats are what all champs have. Wondering why that LB or Zed with 3 items (one being % pen) is nuking you? Yeah, they bought that item and have given you no base stats to survive their combo even if you outplay them right.

Tanks now are not like tanks back in the previous seasons. Runes becoming streamlined removed the tank's ability of running +20 armor or MR at level 1. The removal of that also meant everyone has lower stats than before. That means changing pen was not really called for. In fact, you changed % Pen the same patch you did the failed ADC rework. If they got their stuff partial reverted, then idk why you are allowing % pen to continue to exist as % total.