Working on a Pyro Mercer right now, and it is a nice little kit. The way to tell which is which is that the Vintage Brass and Table Top Classic series had engines and plated parts, while the Table Top Series were more basic, with no engines or plating. Some of the Life-Like reissued didn't have plating, but just molded those parts in silver-grey plastic.
I did have the 30 Packard, and that one had plated parts and separate vinyl tires, so I guess Pyro did make some upgrades along the way.
Oh yes, the Mitchell years at GM produced some of the best looking cars built anywhere, and the mid 60s were when they were at the top of their game. 1967 was also a very good year for styling in Europe. It was the last year of the first gen E-type, the first year of the Miura, and then there were cars like the Lusso, and the Fiat Dino. 1967 was a very good year, but it was not the best year. For the very best year for styling, that would have to be 1931. The was the when you had the definitive classic car shape. The radiator, the headlights, the long hood and swoopy fenders, all in a beautiful combination of form and function. Even decades later, people were trying to capture the magic of this shape, with varying degrees of success.
What's more, variations of it were applied almost universally across the board, in all countries, from the most sumptuous luxury car to the cheapest Model A. True, some were better than others, but outside of some experimental models and the odd lapsed of judgement, I'm hard pressed to think of a car produced during this year that would be considered actually ugly. Obviously some beautiful designs have been produced since them, and you can certainly argue that some of them might be better, but when it comes to consistently producing so many good looking automobile, 1931 is the hands down winner.
I'm all for nice art, but at the same time, all those kits I bought in my youth where pretty box art often meant a vaguely car shaped lump of plastic inside. So, while art is prettier than a photo of the model, my first reaction to no photos tends to be, "Okay, what are they trying to hide?"
Personally, I like Revell's focus on early rods and customs just fine, and I hope they continue. A '26 or '27 T roadster body would be a great addition, perhaps done as a track style rod. I really liked the custom grille and headlights on the last reissue of the '36 Ford, though the option of a chopped top like the AMT kits would be a nice addition should they ever consider reissuing it, as would a set of Lyons hubcaps, or LaSalle style flippers. What I'd really like to see has to do more with the accessories that come with the model. The Deuce grille in the upcoming Model A coupe is a nice option that I would have like to see in the roadster, and it would be nice to see in other T or A based kits. What I'd really like to see is a set of mid 30s Ford style wire wheels to go with the big and little tires that already appear in a few Revell kits. They don't have to be in every kit, but they would be a nice option in at least one.
I can think of all sorts of things I'd rather do with that kind of money, but if you put any kind of reasonable figure on the labour, that's probably what it would end up costing to build, and he did do a pretty nice job of it.
I suppose ultimately it came down to whether they thought the extra effort was worth it. Certainly in your typical plane kit there are also a lot more lines to deal with. In the case of science fiction models, you can say raised panel lines as late as the 90s. However, most companies seem to have thought a proper door panel line was worth it. Tootsietoy was selling cheap diecast toy cars with recessed door panels back in the 1930s. Pyro's competitors released car models with recessed door and hood lines, though in the case of companies like Jo-Han and AMT, they were making promotional items for the car companies, who were willing to invest the money to ensure they looked right. The promo makers weren't doing it to sell toys, but to sell real cars. On a bit of a tangent here, while the carmakers don't seem as interested in promotional models as they were, some are willing to put in the time to design prototypes for video games like Forza, so they're still trying to get potential customers while they're young.