My suggestion for a new game mode:
The car meet, already talked about by forza could have interactions with the characters of the game, Example: you can walk freely in the meet and be able to vote for the cars of the players, have a ranking of the best cars and most voted. It would be something interesting, since the characters in the game are just an “ornament” and have no use, being able to walk around freely at the event would be something very good. A voice and text chat would also be useful, not just messages from the game itself.
Second suggestion: Optimize loading times, the game takes too long to load races, change maps and find online matches.