I don't think they have said much about it, but I haven't watched every single video or some of the foreign language ones. I'm assuming the fact that they haven't said much about it, it means that not much has changed. I'd expect the improvements from FH5 to be brought over, but the system to be basically the same with the layer stacking and so on.
It was confirmed in one interview that we could import our liveries from previous titles, so I'm assuming it works similar to previous games, where you go to the paint shop and tab over to "FM7 Liveries" or "FH5 Liveries" or whatever.
I wouldn't expect anything like GT's svg files, or anything you can do from PC and import though.
What do I know is I'm definitely going back to create new liveries since transfer shouldn't be an issue, I've been relying on old work for years now and I think FM2023 deserves some attention. Since the Nissan R391 is coming, and of course, has plenty of missing logos...