Yeah, I recall hearing that Pratt & Miller are notoriously hard to work with, so I'd totally be fine with a made-for-game Corvette C8 Gr.3.
Also, while I'm always down to see more contemporary race cars - especially for Ferrari and BMW - I don't mind some older cars getting more of their contemporaries, especially since we've seen races that solely feature the Group C cars within Gr.1. In this sense, this is why I'd want to see the 2012 Audi R8 LMS Ultra return from GT6, as I think it'd really round out a trio with the BMW Z4 GT3 and Mercedes-AMG SLS AMG GT3. Not to mention the idea of adding more late-00s GT1 cars to join the Aston Martin DBR9, with the GT1 cars based on the Saleen S7, Maserati MC12, Ferrari 550, and Lamborghini Murcielago seeming like good picks. Sure, Nissan was there, too, but I don't think we need a third Gr.3-spec R35.
EDIT: Here were also some road cars I could definitely see getting listed under Legendary Cars:
Alfa Romeo Giulia Sprint Speciale
Alfa Romeo Tipo 33 Stradale
Alfa Romeo Spider
Alfa Romeo SZ
Aston Martin DB4 GT Zagato
Audi Quattro
BMW M1
Bugatti EB110
Bugatti Type 57
Chevrolet Bel-Air '57
Citroen 2CV
Dodge Shelby Charger '85
Fiat 124 Sport Spider
Ford Falcon (XB) GT
Jaguar XK120
Lamborghini 350GT
Lamborghini Diablo SV (pre-facelift)
Lamborghini Miura P400SV
Lotus Elan
Mercedes-Benz CLK-LM Road Car
Nismo Skyline GT-R (R33) LM Road Going Version
Nissan R390 GT1 Road Car
Nissan Skyline Sport Coupe (BLRA-3)
Plymouth Cuda
Renault Sport Spider
TRD 3000GT
Volkswagen Karmann Ghia
Volvo P1800
Then where were the race cars that'd likely end up in the same place:
Alfa Romeo 6C 1750 '33
Aston Martin DBR1
Audi Sport Quatto S1 '86
BMW V12 LMR
Bugatti Type 37
Ferrari 512S
Ford GT40 Mk.II '66
Honda NSX GT500 '00
Lotus Elise GT1
Peugeot 905
Porsche 959 Rally Car '86
Porsche 911 GT1 '97
Renault 5 Maxi Turbo
Toyota TS010
Toyota GT-One (TS020)