Hello,
Recently I have been climbing the divisions of gold tier mainly playing as an ADC. I have found success mainly with MF, Ezreal, and surprisingly, Ashe. I have enjoyed playing this champions as well as have had numerous very high scoring games with them. Recently I obliged to pick Corki into a team comp consisting of Shaco, Eve, and Twitch. Now given the amount of stealth on their team I figured Corki to be a viable pick. Oh and that was my first mistake. Now I know how to play Corki fairly decently from Season 2 and a little into Season 3 and was comfortable picking him into their composition. Everything just didn't work out as planned. His damage is now mediocre with providing yes, the vision as a utility in this case, but the range is so short in order for me to reveal their stealths I was forced to become incredibly vulnerable to all three as his escape is decent but long cooldown, he is slow, does not have very high damage output, relies on a skill that scales off AP and does magic damage to do his primary source of burst, and just simply doesn't seem to be a good pick at all anymore.
Tl:dr - Corki is weak and needs a buff.
Thoughts / suggestions from other community members appreciated 
GL in season 3 and in the rift!