User blog comment:Deathkin12/Champion Concept: Sly, the Sleeper/@comment-58.172.169.27-20120918122058/@comment-5297851-20120918125922

I think prolonging the sleep would make her imbalanced. It's because yes it is canceled by magic and would cc attackers but think of it, a Veigar could place all his skills properly over a sleeping unit.

I think if it's DotA it's ok since most damage were done by AA but when it come to LoL where most damage is done by abilities, unless you're Vayne, it'll be too overpowered