Thank you for the feedback but this isn't in the current plans for CTA4.
The simplicity of CTA is that it is designed to work with images and drawings. This makes CTA able to animate almost anything you have an image of. Supporting 3D objects in a 3D world space would be turning CTA into a 3D program which we already have with iClone 7.
However, there is nothing to stop you taking a screenshot of a 3D character and then use that image as the source for a character in CTA. Alternatively, if you really want 3D cartoon characters you can use iClone 7 which supports toon characters as well as lifelike human characters.