Why Fnatic Corki?

Janna and Jarvan where no brainers. Gragas was understandable since Shushei is very famous for his Gragas. Karthus is acceptable since he was part of their winning teamcomp, even though Malzahar would have been a much more obvious choice. However, I can't see any reason why Riot decided to give Corki the ADC skin and not Ashe. Anyone have any guesses?