User blog comment:Sifter66/Who do you find is the most Easiest and Hardest Champion to Play?/@comment-3974211-20130224202820

Assuming you mean successfully, rather than mechanically:

Easiest - AP Mid Elise Hardest - Vladimir anywhere (I want to be good with him so bad!)

(I don't play AD-tops, so my list of champions excludes Darius, Renekton, Olaf, Garen, Nasus, Riven, Vi, etc).