You're scaling blitzcrank to be an AD offtank based on what? His ult and q are both really well scaled to AP, and he is far more lethal and useful as burst AP offtank, and plays an important support role. Don't even get me started on the lifesteal, hist attack speed is to slow and not worth trying to improve. AP blitz should be played to burst, harass and support, and AD blitz just shouldn't exist.