Champions that Riot wanted to release years ago but couldn't because they were OP back then?

Lets say In 2011 you created Camile, but you didn't want to release her because her kit was OP in compare to other champs? So you released her years later because her kit was perfect for that season?

So do we have any champs in League that existed for long time but couldnt be released before due to their kit being unsutable for the old season?