I think the tickets should improves as you complete the marathon on consecutive days. Day 1, a part. Day 2 and 3: 3 Stars. Day 4: 4 Stars, so on and so on.
I would like to see some more information added to the world circuits track selection screen (e.g. a couple lines of history, description…) or show a more detailed map with names of the sections/corners.
OR
Add that info to a separate track museum (incl. real photos etc)
It would be cool if the recordings done on PS5 would actually capture the sound like you set it up in game instead of the default sound. Although I'm not sure if this is something PD could do or if it's a limitation of the PS5 firmware.
In livery editor, the ability to review all paints on my car by always pressing "right", instead of "right-right-right-bottom-left-left-left-bottom" and repeat
Offline time trials broken into segments like in CE so that I can practice one segment of a track over and over with a car of my choosing without having to run the whole track to practice the later corners.
Probably not "small" on a technical level but a live free-roam photo mode in online lobbies. That way one doesn't have to start a race to take photos. Having to start a race is kinda inconvenient for drifters and people who just want to take pics of cars.