It puts out more of some kinds of pollution because diesel fule is chock-full of poisonous sulfur. Diesels are noisier, which presents packaging challenges in cars where space and weight are critical considerations. Diesel fuel must be blended to match the change in seasons, to keep from turning into gunk in your car, so it's a bit touchier to handle and distribute than gasoline is. Maintaining diesels is more troublesome and expensive than maintaining gasoline engines. All those aspects would make diesels a hard-sell in the U.S. even if GM hadn't sinned.
Diesel power has tremendous advantages.
The reason I ask is that the structural integrity and subjective solidity of an automobile is very important to me and probably several others. I recall the Lincoln LS and MB E series have natural frequencies of 25 Hz or so. Best I can do is compliment you on your focus. Rigidity and the taut feel it imparts are the heart of good-driving cars. Do they inrease the horsepower and gas mileage.