WHICH New Vehicle Deserves The Most Improved Player Trophy, When Compared Generation-to-Generation?

You have me stumped. I think there are a number of cars are making nice significant moves forward with each generation, certainly the Mustang, the Audi TT-RS, the BMW 2 series (if you consider the 1 series it's predecessor), Mercedes C class... I can't think of one off the top of my head tonight, will be interesting to see what others come up with though.

Given that most of the "features" we are now incorporating into lower vehicles - they almost all started in Higher end vehicles already. I would suggest that small moves forward do not fulfill your requirement. And Unless the change is huge - even a new engine/motor would need to be significantly better as most merely move up by steps. And even then - just a motor change does not make a huge change

I will suggest something that will be ridiculed by others - and is not really that new - but the introduction of the OMEGA platform for the Cadillac CT6 was the biggest leap forward in the last few years. It introduced new multi-metal welding techniques and brought together enough technology to allow the car to get 1000 lbs lighter while STILL giving the Luxury ride of cars a ton heavier. That GM chose a flawed styling aside - I had an early one - and It was really great. Imagine how much higher gas mileage would be if they could reduce the weight of ALL cars similarly. Now - COMPARE that car - to the old generation XTS - the previous Full Size Cadillac Entry - and the CT6 Bests it in almost every way - that is the kind of Change you are talking about. Now look at Lincoln - which replaced the MKS FWD Full size with the New Lincoln Continental. WHile the new Lincoln is nice - it does not begin to compare to the changes in the CT6.

As usual TomM is completely wrong:
Cadillac XTS 4200 pounds
Cadillac CT6 4339 pounds

Maybe I was not as clear as I could have been - The Cadillac Omega Platform WAS 1000 pounds lighter than the equivalent Full Size platforms from Mercedes and Bmw THEN when it came out - and even lighter than the Mercedes, Bmw, and even Cadillac's Mid-size (E/5/CTS class) then

The original BASE MODEL CT6 had a weight of 3,657 pounds - when IT came out in comparison to the weight of the competition THEN.
https://www.inquirer.com/philly/business/cars/20160214_New_CT6_is_light__luxurious.html
https://www.detroitnews.com/story/business/autos/general-motors/2016/01/26/cadillac-ct-makes-red-carpet-debut-oscars/79372692/

AS usual - "Sorrymatt" doesn't bother looking up things that are RIGHT on the internet"

And Tommy's dementia brain scrambles to make his incoherence into something by a flailing do over. Notice too how he does not use accurate CURRENT numbers. Tom go find another friend to Munchausen to death so you can "inherit".

"...McQueen. I still don't understand the man crush over this actor..."

How politically correct of you to "not understand" a real man in this day and age of 741 genders but none of them male.

Steve McQueen was the perfect man. He was smart, talented, good looking, well-rounded, adept at many things and by many accounts rather amazing in bed.

Brings back some memories there (well not the bed part), I first started liking Steve McQueen due to a movie he played in called "The War Lover" which was about a B-17 bomb group in the UK. Since both my grandfather and great uncle were B-17 pilots in the first part of WW II the movies about the air war always interested me. Second boost of McQueen was in a movie called "On any Sunday" about motorcycle racing. Since I was majorly into motorcycle racing of all types at the time, that movie gave me a lot of respect for Steve.

Don't forget that the car chase scene in the movie Bullit did wonders for the Mustang and is one of the best chase scenes ever in movies. Reportedly McQueen did much of the driving.
I'll the chase in Ronin as the best recent chase.
Both the Honda Civic and Acura RDX made huge improvements in recent updates.

McQueen did about half the driving.