Hmm free roaming? Not unless GT Mode, becomes GT Life. That's just too much freedom, that would mean extra rendering of places not necessarily used for racing, which this game is mainly about. For the record, many manufacturers have a thing about allowing their cars in games that have actualy real city streets, hence all games soo far with real city streets are DEVOID of pedestrians and always have crash barriers.
I mean it might be a nice idea, but the execution is what will make it viable, like suppose GT on PS3 is fully online and there are car clubs and you would like to meet and show off your cars, they can implement a car park sort of place where you pull up and hop out your car and pop all the doors, the hood(show casing your engine sans the neon lights), the interior(depending on the level of customization in the game). GT is big enough to have it's own world, but again is dependant on implementation and the money that sony is willing to shell out to get many and i mean many real world after market manufacturers, tuners, tire makers, body part specialists. Even go as far to add real race teams to the full on races(only race spec cars can enter), such as Audi Team Joest, Team Oreca, GM Corvette Team, this sort of thing can give the game such a realistic feeling and much more personal, even allow for manufacturer sponsored races, where you can gain sponsorship by showcasing your skill for different sponsors(unlike the sillyness in Forza). Make the game based on manufacturer relationships, you can still have your garage of thousands or cars, but you can enter manufac. specific races and impress them so they let you drive for them and if done to their utmost, they give you a special car, rare cars the right way. Soo many avenues can be used in GT, PD needs to explore them some more. But one thing, make cars as close to real life as possible, down to the minutests of detail, not just aesthetics, but the engine(manufacturer suggested potential, and potential that tuners have found beyond the manufacturers limits), at least the top tire makers should be included(their real world tire data should make things interesting, making manufac. vs. manufac. races very, very much like real life.
I digress, lemme shut up for now, I'm beginning to drool here.