ADC

Bounding specific champions to specific roles or specific roles to specific playstyles limits the creativity aspect of that role or champion. The bottom lane mage meta was only possible because such technical limitations were not enforced. Renaming the lane or role might not be much, but it can lead to other restrictions (as can be seen for example with the hard restrictions on funneling).

Riot wants to entertain the possibility to play other (creative so to say) champions on the bottom lane than ADCs, so they won't rename it. I'd agree with their assessment by the way.

oh you poor, poor thing...riot doesnt read stuff, didnt you hear deary?

If they changed it to "ADC" from "Bot" then I couldn't proclaim my bot lane Lissandra was meta-breaking gold. :P