A more futuristic dash would be good, wouldn't mind if they continued the rear lights across the back as the red stripe we have that connects between the rear lights doesn't do anything. Not sure that I like the front lights tho, take a bit of getting used to.
Already talked about a lot: the Stinger took its KIA design cues from the Optima. So it only makes sense for the Stinger to influence the Optima in return, not the other way around. The Stinger's more sporty look is altering the Optima. If the Stinger continues, it will be even more impressively dynamic looking - unless they screw it up by going for too much originality: the Stinger's appeal is the retro approach to design cues from 60s and 70s Italian Gran Turismo sports sedans: that's where the fastback hatch, the "jet turbine" circular air vents and the "T" shifter came from. Messing with the interior to make it more "futuristic" will depart from the Stinger concept as a retro design.
As I've said elsewhere: the only thing that doesn't work for me on the teaser pictures of the 2021 Optima is that trunk line across the rear window: like a fastback that has no practical function.