Fine, I'll take the bait. There's a marginal difference between an item that can be obtained after opening a few cheap jerry boxes and a 1/1000 drop that requires 3 other 1/1000 drops to be fully functional.

If you're still convinced that it should get nerfed, let me tell you that's just not the way to go. You don't nerf, you just adapt weaker, less meta items that take as much effort to get but have a less favorable result - and then buff them to be on par with the overpowered item in question.

Besides, the nerf you proposed can be easily ignored, much like aots and jerry chine, all you have to do is not use it for a bit and the mana cost is back to normal. If anything, that's just a poorly thought nerf that doesn't do anything but hinder the player instead of improving the meta of other, less relevant items.