Kog'maw should be reverted to back when his w went past attack speed so he could actually be viable
Kog'maw has been an incredibly weak adc for quite some time since he is too immobile. To compensate for his lack of movement he is supposed to be a glass cannon. He just cant do it quite as well as he could when he could get bonus attack speed and surpass the limit. His damage output would be more balanced with how immobile he is and he could actually be a viable pick again.