There is certainly more that could be done with the dragon knight, but I'm not sure it would necessarily need to be in Divinity 3. There's always Divinity 4...
Project E will have a top down camera view. Most people have been assuming it will be Divinity 3, but no details about Project E have been announced yet (that will come at E3 in June). Besides the general comparison to DD, the only things mentioned have been the camera and fact you would be able to defeat the main bad guy in the end.
