User blog comment:Care Level/Once again, on Attacks v. Spells./@comment-24385282-20150813015847

On one hand, it makes AP and AD essentially the same - for example, when an ADC buys AD they are increasing their basic attack damage, and they have base AD which grows with their level, and when a mage buys AP they are increasing their basic attack damage, and they have base AP which grows with their level. This also, as was mentioned by others, would destroy AD mage builds (ADC Ahri or Annie and of course the classic AD Malzahar).

On the other hand, I have to agree with the point that even with 30% AP scaling on Karthus' autos (not that he'd be getting that much anyway), he's never going to go up to a target enemy champion he wants to kill and decide that he should use a basic attack, it would deal so little damage in comparison to what else he has at his disposal and especially due to the time it takes for him to attack, it would actually slow down a chase or escape and possibly delay his Lay Waste. Additionally, it would be easier to itemize against ranged poke. Now, building MR is good against people who build AP, whereas previously even AP builders could be dealing a decent portion of their damage with physical damage basic attacks, especially in terms of ranged poke.

My only problem with this (aside from rip AD Malz) is it wouldn't work 100%. For example, Katarina, despite generally building all AP and only 40 AD with Hextech Gunblade should she choose to purchase it, will still be dealing physical damage which scales off AD, simply because she attacks with swords.