User blog comment:Commander Marko/What's Riot really up to?/@comment-4652200-20130815002950/@comment-4022742-20130815104058

My guess is that they are learning from their mistakes. They don't want another who lost her identity and was Under Powered after rework, which resulted in a lot of people trying their best to make her work, bot not succeeding.

And they don't want another, who is strong in his current iteration, up to the point where he is either in the ban list, or just obliterates teams in late game. Rarely have I seen a YI do bad, even when he was 0/7/4 from lane phase, he still farms up and ends with decent scores.

So they want to be absolutely sure they don't end up with on one end of those extremes. That's my best guess.