Really... this post ...

http://38.media.tumblr.com/ae9a7eec9b54f7522ff09cc7cc01fb47/tumblr_mjxa2jnvn21rdpc1ao1_r1_400.gif

There were probably a lot of posts for every possibility, so one of em had to be right! Sivir, Jinx, Graves, Tristana, Ashe, Varus maybe some other and Azir (ya he's marksman) all had huge impact early on and they probably had it picked by mid season so probably wasn't Vayne.