Just to avoid doubling the work for that character (or the hassle of allowing it to be configured), if the Dragon Knight is in the next game it would probably be easiest to change the model away from anything that was available in D2:ED/DKS and have him/her make a comment about taking advantage of the illusionist. Alternately, that character could remain in dragon form.
If they go with a fixed character, I'd guess they would make the dragon knight female, at least for contrast with the Divine One (who is male in D2:ED, but you could play a male or female character in Divine Divinity).
