The Pen on Rage Blade is Unnecessary

They're pushing it to be less only for champions who build full on-hit I think. It's still odd though because now building it alongside Wit's End is counter-intuitive.

Instead of pen, they should have increased the on-hit damage each hit. For example, the first hit does 15 on hit magic damage, then every hit does 2 more. In other words, 15, 17, 19, 21, 23, 25, then 27 at full stacks. However, doing so would make the item too similar to wit's end. Maybe stack physical on-hit instead of more magic?