I think that, when it comes to the TTS, PD weren't smart about it. They could have opted for the RS version, which would differentiate it from the existing 2014 TTS and the TT 3.2, while also being the first Audi RS model in the game. This is the strategy to diversify the car list even for different generations of the same model.
The same for the R8: R8 4.2 (gen 1), R8 V10 Plus 2015 (gen 2) and R8 V10 GT RWD 2023 (gen 2, post facelift, rear wheel drive "track" version). You could do this for plenty of other Audis.
And plenty of brands could use this "strat".
We have the A45 AMG from 2013, and to update the line up, we could get the 2020 CLA45 S AMG, which is pretty much the sedan version of the newer A45.
The Renault 4, yes, I think it's a weird/meme choice, that feeds off the nostalgia of a percentage of the player base. Some people will use the "it did rallying" as a reason, although almost anything was used for rally at some point, with some real rally cars/cars with real rally pedigree (like the 70s Ford Escorts) being much more relevant in that regard. And engine swaps shouldn't be the sole reason to add a car to the game. But I'm yet to understand what is the criteria PD uses to model cars, because at this point, it's assumed that they just stumble upon something, and decide to add it.
The thing is, PD isn't even doing a good job at modeling road cars. There's probably over 500 road cars that would fit really well into the game, yet they managed to choose road cars outside that sphere, and completely ignoring the glaring omissions. The best update yet, had 7 cars, and atleast 6 of them were in most people's wishlist at some point.
No one is really expecting a steady stream of GT3 cars, but a few here and there (Ferrari and Aston, and then Bentley) would make a huge difference.
That's not how it works. PD can only model a limited amount of cars per year (some say it's 60 per year). Of which some are added to GT7 via update, the rest probably saved for the next game. Having paid DLC, won't magically increase the number of cars they can model in a year.
And given their track record, even as road cars go, chances are we would still get road cars that nobody asked for, so not only you would be forcing those who want race cars, to pay extra to have them, and those who want good road cars forced to endure meme cars, duplicates, and so on.
