Give oblivion orb the antiheal and give the full item of 
the magic pen to stop AP from snowballing too early, whilst making oblivion orb more of a strategic item.
One question too, someone disagreed and said this would shift mages to top lane xD
Can anyone factually support his claim?
The reason why GW being on Oblivion Orb would shove a bunch of mages into top lane has nothing to do with combat weirdly enough.
So for example here lets use Aatrox who has built in healing vs a top lane mage like Ryze was.
Aatrox wins that lane currently because he can sustain the damage and if he manages to get on top of Ryze, he can almost 1 shot Ryze.
But now add in the 1600 GW - M Pen. Aatrox no longer can sustain in the lane because Ryze goes up and clicks E once every 3 seconds. (Only when minions stack up).
This now makes Aatrox function like old top laners vs mages. He has to sit back and just give up the game to scaling mages.
I can understand that bit.
But on the same note, mages should have access to GW before a completed item. The reasoning being as follows.
Mages often time can't deal with the sustain that champions with Sustain bring. We've seen champions go into mid lane that belong in top lane because they had some insane healing prowess. Irelia and Akali were offenders when in their prime. Aatrox before getting gutted. This is before accounting for early fights in the jungle/river. Where healing power is amped by external sources such as smite, heal, plants, abilities on other teammates.
I wouldn't be saying this is bruisers/fighters/scrimishers didn't get access to so many nice items. They have access to MS from phage on two items (tri force and BC), Adaptive Helm/Spirit Visage, Spear of Shojin, Steraks. The funny thing is taht they only need two offensive items to blow people up. Renekton with Black Cleaver, Spear, + all defensive items.
While mages have to get Ludens/Seraphs > Offensive boots > Morello > Rabadons > Zhonya's > Void to be able to fully kill a Renekton, while only getting 1 defensive item.
AP items need to be reworked, fighters need to not be able to dip into ADC items, and Tank Items.
Maybe bcause it would counter all conqueror users and sustain champs? IDK only thing I can come up with
I would say it is because penetration is more useful when you have half an item than a whole item
Not really sure, if there are more "toplaner" with self heal, than mid. But even if there are i fail to see why mages on top would be a bad thing. Though it would also improve them on botlane against healer supports. Not forcing the ADC to buy early exe.
To be honest i would remove the entire heal reduction mechanism, and adjust heal values instead. Kinda sad, that one item can broke certain champs, and the missing of that item can make them overpowered.
Imagine a tank/support item. If you hit the champ. wearing this item, or get hit by that champ, then all your damage done gets reduced by 50% for 2 seconds. Including true damage. Costs 1000, and can be upgraded with extra armor, and mr for another 1500. The upgraded version gives the effect for 4 seconds instead of 2.
Mages already go top or mid depending on matchup, but the double pen rush allows them do burst really hard really fast (but at the cost of less waveclear) this allows them to roam really well. Will this cut down on mid lane mages? No they just will go full ap instead of pen honestly it will only make them stronger vs sustain laners but weaker vs ones that need be bursted so top>mid would be theoretically a thing, but most mages would simply opt to go lich/ludens/etc first or become tankier with rylais liandrys. More viable top yes, less viable mid yes, unviable mid? no.
AP is a snowball stat. Making it not snowball early is absurd.
