* [**Removed**] No longer grants promoted minions immunity to magic damage
This has always been bullshit. It was bullshit to play against as an AP champion, especially a mage. The only reason why it "wasn't a problem" before is because for some reason, this item was rarely purchased before. But now it is a very popular purchase.
It is bullshit because as an AP, you literally can do nothing to get rid of that damn promoted minion (save for a few outliers that have physical damage or true damage in their kits, like Akali or Vel'Koz). Using spells against it is a complete waste of time (and mana, for most APs), and using autos against it is worthless as AP's autos tend to be laughable (the few that aren't, do magic damage, so they are still worthless).
This item just invalidates certain champions. And for other champions, it can make an otherwise bad matchup a very manageable, if not favorable matchup. For example, Vladimir used to be a counter to Singed, but now Singed can just buy Banner and watch as Vlad can do nothing except see his tower being taken. It also makes Sion mid viable, which, while increasing diversity (it is good to see a tank being viable mid), Sion is a pain in the ass to deal with for mages.
Also, as you may remember, in One for All, this item alone completely destroys compositions with champions that deal almost exclusively magic damage, like the majority of mages, unless one of them builds AD.
At same time, however, this item has little use against ADs because they have an easy time clearing it. Which is weird, because this item offers more armor than magic resistance. This makes it even more bullshit, as an AP shall never ever be invalidated by an item that offers stats that are actually better against physical damage (compared to magic damage).
This item was supposed to be a counter to heavy waveclear mages, but making it 100% immune to magic damage was the worst solution possible.
Making it 70% resillent to all champion damage means not only this item isn't impossible to deal with for mages, but it is also significantly better against ADs. Which is what this item should have been since the beginning.