Morellonomicon's two unique passives and Void Staff variants

Small disclaimer: I play mostly ARAM, so whether this suggestion is bested suited for SR-only, ARAM-only, or both SR and ARAM is open to discussion.

Morellonomicon is a huge power purchase for mana-using mages thanks to 100 AP, 20% CDR (edited in, was sleepy and forgot!), mana regen on takedowns, and the Grievous Wounds effect. It's a huge amount of power packed into one item. In many situations, you could say it's a must-buy for mages. However, there are times when Morellonomicon would not fit so nicely into a champion's build, but the two unique passives that the item provides would be sorely missed.

Given the two variants of Last Whisper, I wonder if two variants for Void Staff could be created that would each include one of the Morellonomicon passives. In short:

Void Staff Variant A +80 ability power UNIQUE: Magic damage ignores 35% of the target's magic resistance UNIQUE: Dealing magic damage to an enemy champion below 35% health inflicts Grievous Wounds to them for 8 seconds.

Void Staff Variant B +400 mana +80 ability power UNIQUE: Magic damage ignores 35% of the target's magic resistance UNIQUE: Kills and assists restore 20% of your maximum mana

Edit: I'm not suggesting we remove effects from Morellonomicon, but to duplicate its passives elsewhere.

Now, I know magic penetration as a whole is a different entity than armor penetration, so a one-to-one comparison of Last Whisper to Void Staff is not ideal. Still, I think the passive effects on Morellonomicon could and should make their way onto other items. Whether those items should be Void Staff variants can be contested by the community or Riot, but in any case, feedback is appreciated.

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Some notes

1. Like Executioner's Calling, an Amp Tome upgrade for the Grievous Wounds effect could be incorporated into the build paths for Morellonomicon and the new Void Staff.
2. The unique passives for Morellonomicon could receive names that would unify the passives on the Void Staff variants. For example, you could name the Grievous Wounds effect "Virology" and the mana restore effect "Lost Arcana". I'm not good with naming things, so feedback appreciated.
3. +400 mana on a Void Staff item might be extreme for mana-scaling champions (e.g. Ryze), so this value could be adjusted to +300 (same as Lost Chapter). The passive effect is the important element to retain.
4. If these Void Staff variants would increase the cost of the item and thus delay magic pen beyond what's healthy for the game, a component Void Staff could be added that's similar to the component Last Whisper. For example, builds out of Blasting Wand and gives 40 AP and 20% magic penetration.