Mitsubishi Lancer Evolution X FQ-400 '10
Ford Focus RS '09
Bugatti Veyron '09 (Premium)
Suzuki Swift Sport '12
TVR Sagaris '06
Volkswagen Beetle '12
I think it's not a good idea to ask for new models of cars we already have nor upgrading standard cars to premium status and offer them as DLC. That shares the same problem with "duplicates" (having 40 useless versions of the same car), which is it doesn't feel like new content is being added to the game hence it's a wasted effort in PD's part and a waste of customers money.
DLC Pack #1 had the most requested feature, which was more RM cars and called them TC. Problem was there were only 4 new ones out of 15.
Some already had RM versions (challenger, evo, impreza) and others were repeated or simply didn't improved the game, such as the X2011 (I also find absurd there are 3 versions of that car), karts (would have been different if those were karts with shifters and more hp, or less powerful yet more common karts), and more and more skylines.
DLC Pack #2 featured 4 cars, but in reality only 1 was truly an addition to the game. We already had a mini cooper S, a Golf and a gazillion GT-Rs.
Finally, DLC Pack #3 had 6 cars but 3 were "repeated", which are the XJR-9, the beetle and the countryman S FWD version (would have been different if PD used the 4wd one, which is mini's current base model for WRC).
Probably I'd be still playing GT5 if those 3 packs were done properly, with 25 new cars instead of 8.