I'm really looking forward to the new cars! I do think that Alsace could likely obtain a new layout, but I wouldn't rule out Sardegna nor Colorado Springs, either. Northern Isle could be in there, too. As for other new courses vs. layouts, I could see other GT-original courses returning, given that Kaz said they're working on Deep Forest. Personally, I'm almost down for almost any course from prior games - original or real-world - returning, including historic layouts of courses we have, like the 80s layout for Fuji, or the 2005 version of Le Mans.
With all this in mind, I'd like to see some minor additions to the livery editor. Specifically, I'd like to see the other course logos be added, and I'd like an option for the driver name to have custom text & a selected flag, rather than just using your PSN name. Like if you wanted to replicate a different livery, or use your real name. It could even have the option to have you add up to three driver names, much like how you can see multiple names on some default liveries already, like the Hyundai N2025 VGT or the Super GT500 cars.