Greatest Marketing or design items?:
When you ask about that subject, I think about items that showed up in marketing, not just in your experience with the actual car. More about expectations and driving people to desire a car as opposed to what they actually got. Here are some thoughts on that:
Self-winding steering wheel clocks: http://imperialclub.com/Yr/1958/Benrus/index.htm
First single piece windshield and true aero-dynamic, wind-tunnel induced styling in a production car (airflow) (only on Imperial!!)http://imperialclub.com/Articles/Trifon/index.htm
"red -head" in the 1920's - long before that guy Enzo started advertising testarossas in the 50's. http://imperialclub.com/Yr/1928/Ads/index.htm
Show Cars: http://imperialclub.com/Rare/ShowCars.htm
THE FORWARD LOOK http://imperialclub.com/Yr/1957/FwdLkAd/index.htm
And Don't forget Virgil! http://imperialclub.com/Articles/Exner/index.htm http://imperialclub.com/Articles/Exner/Jr/index.htm
Fluid Drive semi-automatics that predated automatic trans and appeared just before the war. http://imperialclub.com/Yr/1940/Ads/index.htm
Air conditioning and power windows just before/after the war. http://www.dte.net/57imperial/50saga/index.htm
Floating Power motor and trans mounts (that's a biggie, folks)http://imperialclub.com/Yr/1932/Ads/index.htm Most cars had little dampening.
"Hemi" http://imperialclub.com/Articles/51Hemi/index.htm
"440" http://imperialclub.com/Repair/Engine/440.htm
Torqueflight (never had a recall) http://imperialclub.com/Repair/Lit/Master/140/index.htm
Headlight doors http://imperialclub.com/Yr/1969/Brochure/index.htm
Auto Pilot http://imperialclub.com/Articles/58AutoPilot/index.htm
Turbine engines (could have been Imperial if only....) http://imperialclub.com/Yr/1963/Turbine/index.htm
Mark Cross, Frank Sinatra editions. http://imperialclub.com/Rare/Factory.htm
1967 Mobile Director option http://imperialclub.com/Yr/1967/MobileDirector/index.htm
Ghia "Halo Car" parade cars and limos http://imperialclub.com/Rare/Phaetons/1950s/index.htm http://imperialclub.com/Articles/64-65Ghias/index.htm