Why are people always so concerned about the Uncanny Valley effect? It is a filmmaker's choice, not inherent to a product, such as iClone.
I know there are those that think that animation should look a certain way and no other, but I think that is limiting yourself unnecessary. Fortunately, there are many different ways in which animation is expressed through many different mediums, if you know where to look.
What I like about iClone is that there are indeed many possible looks: surreal, semi-realistic, epic, toon, etc. It's all in the artist's hands. Just check the "Showcase yourself" section.
The toon shader was introduced after iClone had been around for some time. It could certainly be improved and should, but as an alternative look among many possible iClone looks, not as a remedy against a presumed "Uncanny Valley" syndrome.
And who knows, with a plugin architecture in IC6, the door may be opened to all kinds of render options, including a serious toon shader. I would support that and might even use it myself.