AP itemization ideas: Magic Penetration

I have lots of ideas for the upcoming AP item pass that I want to share with you. Keep in mind, this ideas might be bad and numbers are just for reference.

Magic Pen is one of the major issues of AP Items right now, and I have some ideas to fill the gaps they have at the moment. Burst Mages should not significantly damage tanks unless ahead, and that's why %penetration has been reduced. However, there's a new Black Cleaver-like item for Battle Mages!

-Flat Penetration line

Lethal Flame 1500g: + + 630g +40 AP Unique Passive - Deathfire: +15 Magic Penetration

Deathfire Grasp 3400g: Lethal Flame + + 650g +120 Ability Power Unique Passive - Deathfire: +15 Magic Penetration Unique Active - Doom: Target enemy is marked with Doom for 4 seconds. Doomed enemies store 20% of the damage they take from you and ONLY you, and when the mark expires they take that damage again (500 range). (Like a mini Zed ult)

This iteration of Deathfire Grasp gives it counterplay (the damage is delayed) and solves the issue of it being used as one more nuke to take a target instantly (it deals no damage by itself, it needs you to deal the damage). It also has reduced range to be less attractive to mages and more to melee assassins.

Deathfire Pact 3400g: Lethal Flame + + +700g +100 Ability Power Unique Passive - Deathfire: +15 Magic Penetration Unique Passive - Dark Gift: Your first Ability against an enemy Champion deals 5-10% (based on level) of their current health as magic damage. Cooldown: 20 seconds.

-% Penetration Since this kind of penetration is more generalistic, is included in a single item with a Black Cleaver-like Passive. Haunting Guise reworked to a simple AP+Health item, and costs 100g more than Phage.

Liandry's Torment 3200g: + + 1050 +400 Health +60 Ability Power +20% Cooldown Reduction Unique - Dealing magic damage to champions reduces their armor by 4% for three seconds, stacking up to 24%. Unique - Your next damaging ability landed on an enemy champion grants you 10% bonus movement speed for 2 seconds. Cooldown: 10 seconds.

-% Bonus Penetration line

[Reworked] Void Staff 1300g: +865g +20 Ability Power Unique - Void Staff: +25% Bonus Magic Penetration

Void Staff - Lina's Enchantment 3000g: + + + 900 +350 Health +70 Ability Power Unique - Void Staff: +35% Bonus Magic Penetration Unique: [Current Liandry's burn passive]

Void Staff - Kaldr's Enchantment 3000g: + + + 900 +350 Health +70 Ability Power Unique - Void Staff: +35% Bonus Magic Penetration Unique: [Current Morello's Grievous Wounds passive]

That's all, folks! Share your opinions of them and feel free to comment why or why not would they be good for the game.