Hybrid Pen Runes, But No Items?
I find it a little strange that we have hybrid penetration runes in league of legends but not hybrid penetration items, which I feel could easily be done without having to build any new items, and would offer more health options for those bruisers and champions who deal hybrid damage like Jax, Udyr, Kayle.
Obviously this is just an experimental item but why not have Haunting Guise + Serrated Dirk build into something called Twin Gaze where you gain 15+ magic pen and 15+ armor penetration. An item like this could work well on Corki, Jax, Malzahar's voidlings, Kayle, possibly Yorick though he doesn't do magic and physical damage at the exact same time with autoattacks the way the aforementioned champions do.
Part of me thinks this could lead to some toxic bullshit, because popular opinion seems to be that hybrid champions are either worthless, or completely broken. So my question, is should a hybrid penetration item come out, this way hybrid champions can continue to rev up their damage, and not be forced to rely solely on runes, which is slightly annoying from a customization stand-point. It just feels so odd that we have armor and magic pen runes as well as hybrid runes, but no actual hybrid penetration items, and I think it would provide an interesting option for those hybrid fighters and perhaps leave more room to balance them.

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In the case of most legitimate hybrid-damage champions, hybrid armor penetration items wouldn't be game breaking. It would probably help such champions scale well into late-game without falling into the 4 major-item rut a lot of bruisers find themselves in.
The issue would mostly be around champions like Jax, Kayle, Corkie, Akali, and more essentially pulling off a tanky assassin deal where they're breaking the game with items not intended for them.