As you said affection items. I already think its balanced if Vette is more light and Jaesa is dark. You can use the same thing you said yourself for Jaesa as dark warriors can use for Vette.
With that said I agree and disagree. I agree light side should have the option to romance a light Jasea and disagree that Jaesa be only light. She should be able to have a romance with both. Just like all romance options in my opinion should be for both, not one or the other.